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1.  Evolutionary Dynamics of Variant Genomes of Human Papillomavirus Types 18, 45, and 97▿ †  
Journal of Virology  2008;83(3):1443-1455.
Human papillomavirus type 18 (HPV18) and HPV45 account for approximately 20% of all cervix cancers. We show that HPV18, HPV45, and the recently discovered HPV97 comprise a clade sharing a most recent common ancestor within HPV α7 species. Variant lineages of these HPV types were classified by sequence analysis of the upstream regulatory region/E6 region among cervical samples from a population-based study in Costa Rica, and 27 representative genomes from each major variant lineage were sequenced. Nucleotide variation within HPV18 and HPV45 was 3.82% and 2.39%, respectively, and amino acid variation was 4.73% and 2.87%, respectively. Only 18 nucleotide variations, of which 10 were nonsynonymous, were identified among three HPV97 genomes. Full-genome comparisons revealed maximal diversity between HPV18 African and non-African variants (2.6% dissimilarity), whereas HPV18 Asian-American [E1 (AA)] and European (E2) variants were closely related (less than 0.5% dissimilarity); HPV45 genomes had a maximal difference of 1.6% nucleotides. Using a Bayesian Markov chain Monte Carlo (MCMC) method, the divergence times of HPV18, -45, and -97 from their most recent common ancestors indicated that HPV18 diverged approximately 7.7 million years (Myr) ago, whereas HPV45 and HPV97 split off around 5.7 Myr ago, in a period encompassing the divergence of the great ape species. Variants within the HPV18/45/97 lineages were estimated to have diverged from their common ancestors in the genus Homo within the last 1 Myr (<0.7 Myr). To investigate the molecular basis of HPV18, HPV45, and HPV97 evolution, regression models of codon substitution were used to identify lineages and amino acid sites under selective pressure. The E5 open reading frame (ORF) of HPV18 and the E4 ORFs of HPV18, HPV45, and HPV18/45/97 had nonsynonymous/synonymous substitution rate ratios (dN/dS) over 1 indicative of positive Darwinian selection. The L1 ORF of HPV18 genomes had an increased proportion of nonsynonymous substitutions (4.93%; average dN/dS ratio [M3] = 0.3356) compared to HPV45 (1.86%; M3 = 0.1268) and HPV16 (2.26%; M3 = 0.1330) L1 ORFs. In contrast, HPV18 and HPV16 genomes had similar amino acid substitution rates within the E1 ORF (2.89% and 3.24%, respectively), while HPV45 E1 was highly conserved (amino acid substitution rate was 0.77%). These data provide an evolutionary history of this medically important clade of HPVs and identify an unexpected divergence of the L1 gene of HPV18 that may have clinical implications for the long-term use of an L1-virus-like particle-based prophylactic vaccine.
PMCID: PMC2620887  PMID: 19036820
2.  Human papillomavirus type 16 sequence variation in cervical cancers: a worldwide perspective. 
Journal of Virology  1997;71(3):2463-2472.
We examined intratype human papillomavirus type 16 (HPV-16) sequence variation in tumor samples that were collected and analyzed in an international study of invasive cervical cancer. The collection included tumors from 22 countries in five continents. Using our recently developed E6 and L1 PCR-based hybridization systems to distinguish HPV-16 variant lineages, we analyzed material from tumors previously found to contain HPV-16 DNA. Of 408 specimens analyzed in the E6 hybridization assay, 376 (92.2%) belonged to previously reported HPV-16 variant lineages. The remaining 32 specimens (7.8%) harbored HPV-16 variants with novel hybridization patterns, novel nucleotide changes, or both. Nucleotide sequences (1,203 bp) were determined for the E6, the MY09/11 region of L1, and the long control region of each novel variant and representative specimens from each hybridization pattern observed. Based on E6 hybridization patterns, most of the variants from European and North American samples were phylogenetically classified as European prototype (E) while samples from Africa contained primarily African 1 (Af1) or African 2 (Af2) variants. The majority of Asian (As) variants were observed in Southeast Asia, and almost all Asian American (AA) variants were from Central and South America or Spain. A single North American 1 (NA1) variant was detected in a tumor from Argentina. Nucleotide changes previously shown to covary between the MY09/11 region of L1 and the E6 coding region were examined in a subset of 249 specimens. We observed 22 combined E6-L1 hybridization patterns, of which 11 (in 21 samples) were novel. No unanticipated nucleotide covariation was observed between the E class and the AA-Af1-Af2-NA1 classes, suggesting the absence or rarity of genomic recombination between HPV-16 lineages. This extensive description of HPV-16 variants forms a basis for further examining the relationship between intratype variation and basic functional differences in biological activities. HPV-16 variants may prove important for the determination of the risk of cervical neoplasia and for the design of HPV-16 vaccine strategies.
PMCID: PMC191357  PMID: 9032384
3.  Human Papillomavirus Type 16 Variant Analysis of E6, E7, and L1 Genes and Long Control Region in Identification of Cervical Carcinomas in Patients in Northeast China ▿ 
Journal of Clinical Microbiology  2011;49(7):2656-2663.
Human papillomavirus type 16 (HPV 16) plays a cardinal role in the pathogenesis of cervical cancer. HPV 16 has intratypic variants which show different geographical distributions and different oncogenic potentials. To analyze the presence of sequence variations of HPV 16 variants in northeast China, 71 cervical carcinomas were identified by HPV typing. HPV 16-positive specimens were analyzed by PCR-directed sequencing in the E6, E7, and L1 genes and the LCR (long control region). The variation data were compared with those of neighboring districts. In this hospital-based study, HPV 16 was the most common type (73.24%). In HPV 16-positive specimens, 67.31% belonged to the European (E) lineage, while 32.69% were Asian (As) variants. The Asian-American (AA), African-1 (Af-1), African-2 (Af-2), and northern American (NA) lineages were not detected. The most frequently observed variation sites were T178G (32.69%) in E6; A647G (34.62%), G666A (38.46%), and T846C (32.69%) in E7; C6826T (36.17%) and G7060A (61.70%) in L1; and G7521A (98.08%) in the LCR. The most prevalent amino acid variations were D25E in E6 and N29S in E7. In addition, 28 novel variations of HPV 16 were reported. Some covariations between different genes were obtained. In this study, HPV 16 variants belonged to the European lineage and the Asian lineage. Compared with neighboring districts, the distribution of HPV 16 variants in northeast China had a typical pattern. As the first report on HPV 16 variants in northeast China, it should be helpful for designing a HPV vaccine and HPV vaccination program in China.
PMCID: PMC3147813  PMID: 21593270
4.  Association of human papillomavirus type 16 long control region mutation and cervical cancer 
Virology Journal  2013;10:30.
The variation of human papillomavirus (HPV) genes or HPV variants demonstrates different risks of cervical cancer. Mutation in the long control region (LCR) at YY1-motifs is one of the mechanisms for enhancing viral oncogene expression during the course of cancer cell progression. In Thai women, cervical cancers are almost always associated with HPV16 variant sub-lineage Asian (HPV16As); however, the mechanism involved remains elusive. The aim of this study was to understand further the oncogenic potential of HPV16As.
A total of 82 HPV16-positive specimens from Thai women were selected from formalin-fixed paraffin-embedded cervical tissues, and the full length E6 gene of each specimen was amplified and sequenced. LCRs of the HPV16As-positive cases were amplified and sequenced to analyze their polymorphisms. Transcriptional activities of the HPV16As LCRs were then compared with sub-lineage European (EUR), sub-lineage Asian-American 1 (AA1) and HPV16 prototype by insertion of the LCRs into the pGL3-Basic vector.
The HPV16 DNA sequences were classified as HPV16 prototype (18.3%), Asian (As, 61%), Asian American-1 (AA1, 8.5%), European (EUR, 7.3%), Asian African-2 (AFR2, 3.7%) and Java-135C (J135C, 1.2%). The prevalence of HPV16As was 30% in low-grade squamous intraepithelial lesion (LSIL), while that in high-grade squamous intraepithelial lesion (HSIL) and squamous cell cervical carcinoma (SCC) were 63.9% and 66.7%, respectively, which demonstrates a significant association of HPV16As with the disease severity. LCR polymorphisms from 43 HPV16As positive cases were analyzed by PCR-sequencing. Thirty-eight nucleotide variation positions spanned nucleotide positions 7157–82. Ten new mutations found in the HPV16As LCRs were located predominantly at the enhancer and proximal to the 3’-end of the early promoter. The LCRs of the common HPV16As, EUR and AA1 showed 5, 13 and 23-fold higher activity than the HPV16 prototype LCR, while those of the new nucleotide variations of As showed 19 (As-sv1) and 30 (As-sv14) -fold higher activity than the HPV16 prototype.
HPV16As DNA sequence variation, especially at the proximal to early promoter in the LCR, enhances transcriptional activity. This could be one of the possible mechanisms for HPV16As-associated cervical cancer development.
PMCID: PMC3599568  PMID: 23343096
HPV16; Sub-lineage Asian; Cervical cancer; Long control region
5.  Analysis of mutations in the E6 oncogene of human papillomavirus 16 in cervical cancer isolates from Moroccan women 
BMC Infectious Diseases  2013;13:378.
Worldwide, cervical cancer is the second most common cancer in women. High-risk human papillomavirus (HPV) play a crucial role in the etiology of cervical cancer and the most prevalent genotype is HPV16. HPV 16 intratypic variants have been reported to differ in their prevalence, biological and biochemical properties. The present study was designed to analyze and identify HPV type 16 E6 variants among patients with cervical cancer in Morocco.
A total of 103 HPV16 positive samples were isolated from 129 cervical cancer cases, and variant status was subsequently determined by DNA sequencing of the E6 gene.
Isolates from patients were grouped into the European (E), African (Af) and North-American (NA1) phylogenetic clusters with a high prevalence of E lineage (58.3%). The Af and NA1 variants were detected in 31.1% and 11.6% of the HPV16 positive specimens, respectively, whereas, only 3% of cases were prototype E350T. No European-Asian (EA), Asian (As) or Asian-American (AA) variants were observed in our HPV16-positive specimens. At the amino acid level, the most prevalent non-synonymous variants were L83V (T350G), H78Y (C335T), E113D (A442C), Q14D (C143G/G145T) and R10I (G132T), and were observed respectively in 65%, 41.8%, 38.8%, 30.1% and 23.3% of total samples.
Moreover, HPV16 European variants were mostly identified in younger women at early clinical diagnosis stages. Whereas, HPV16 Af variants were most likely associated with cervical cancer development in older women with pronounced aggressiveness.
This study suggests a predominance of E lineage strains among Moroccan HPV 16 isolates and raises the possibility that HPV16 variants have a preferential role in progression to malignancy and could be associated with the more aggressive nature of cervical cancer.
PMCID: PMC3751500  PMID: 23953248
Cervical cancer; Human papillomavirus 16; Variants; E6; Morocco
6.  Human papillomavirus type 16 sequence variants: identification by E6 and L1 lineage-specific hybridization. 
A catalog of human papillomavirus (HPV) type 16 (HPV-16) E6 and L1 signature nucleotides was used to develop PCR-based oligonucleotide probe systems capable of distinguishing HPV-16 class and subclass variants. Twenty-three E6-specific oligonucleotide probes targeting 13 variant nucleotide positions and 12 L1-specific oligonucleotide probes targeting 6 variant nucleotide positions were used to characterize HPV-16-containing cervicovaginal lavage specimens. Nucleotide positions that could be distinguished included E6 nucleotides 109, 131, 132, 143, 145, 178, 183, 286, 289, 335, 350, 403, and 532 and L1 nucleotides 6695, 6721, 6803, 6854, 6862, and 6994. Combined hybridization patterns were assigned on the basis of the predicted HPV-16 class, subclass, or minor class variants described previously (T. Yamada, C. M. Wheeler, A. L. Halpern, A.-C. M. Stewart, A. Hildesheim, and S.A. Jenison, J. Virol. 69:7743-7753, 1995). The major HPV-16 variant lineages detected included European prototype-like (E-P), Asian (As), Asian-American (AA), and African (Af1 and Af2) lineages. In addition, E-G131, an E-class variant, and AA-G183, an AA-class variant, were also identified. For each clinical specimen, DNA hybridization results were compared to nucleotide sequence determinations. Targeted L1 and E6 marker nucleotides covaried within all HPV-16 variant isolates examined. These hybridization-based methods result in minimal misclassification error, are amenable to targeting additional lineage-specific nucleotide positions, and should facilitate the large-scale, low-cost analysis of HPV-16 variants in epidemiologic investigations. Specifically, these methods will facilitate epidemiologic studies of HPV-16 transmission and natural history, as well as studies of associations between HPV variants, host immune responses, and cervical neoplasia.
PMCID: PMC229505  PMID: 8968874
7.  Evaluation of a Commercialized In Situ Hybridization Assay for Detecting Human Papillomavirus DNA in Tissue Specimens from Patients with Cervical Intraepithelial Neoplasia and Cervical Carcinoma▿  
Journal of Clinical Microbiology  2007;46(1):274-280.
To evaluate a commercialized in situ hybridization (ISH) assay for detecting human papillomavirus (HPV) DNA, we compared the ability of a new ISH probe, Inform HPV III (Ventana Medical Systems, Tucson, AZ), to that of PCR assays to detect HPV DNA in cervical tissue specimens with normal cervix (20 cases), cervical intraepithelial neoplasia (CIN; CIN 1, 27 cases; CIN 2, 28 cases; and CIN 3, 33 cases), and cervical carcinoma (29 cases). General HPV DNA was detected using consensus primer-mediated PCR assays. HPV genotyping was performed by using EasyChip HPV blot (King Car Yuan Shan Institute, I-Lan, Taiwan). HPV16 integration status (E2/E6 ratio) was determined by using quantitative real-time PCR. Our findings showed that the ISH and PCR had fair to good agreements in detecting HPV DNA across all CIN categories without significant differences (Kappa coefficient, 0.34 to 0.63; P = 0.13 to 1.0). However, ISH detected significantly fewer HPV-positive cases in carcinoma than PCR did (Kappa coefficient, 0.2; P = 0.03). Eleven cases with ISH− PCR+ results had HPV types that can be detected by Inform HPV III. Five carcinoma cases with ISH− PCR+ results showed a significantly higher level of integrated HPV16 (P = 0.008) than did the ISH+ cases. As a consequence, lower copy numbers of episomal HPV16 in carcinoma might be the cause for the false-negative ISH results. Although the punctate signal pattern of HPV significantly increased with the severity of disease (P trend = 0.01), no significant difference in the HPV16 integration status was observed between the cases with a punctate signal only and the cases with mixed punctate and diffuse signals (P = 0.4). In conclusion, ISH using the Inform HPV III probe seems comparable to PCR for detecting HPV DNA in cervical tissue with CINs. False-negative ISH results appear to be associated with the lower copy numbers of the episomal HPV16 but not with the ability of the Inform HPV III probe to detect specific HPV types. In addition, signal patterns, especially a mixed punctate and diffuse pattern of HPV, cannot be reliably used to predict viral integration status.
PMCID: PMC2224284  PMID: 17977987
8.  Molecular tests for human papillomavirus (HPV), Chlamydia trachomatis and Neisseria gonorrhoeae in liquid-based cytology specimen 
BMC Women's Health  2009;9:8.
Laboratory detection of Human papillomavirus (HPV), Chlamydia trachomatis and Neisseria gonorrhoeae in liquid-based cervicovaginal cytology specimens is now based on identification of the DNA sequences unique to these infectious agents. However, current commercial test kits rely on nucleotide probe hybridization to determine DNA sequences, which may lead to diagnostic errors due to cross-reactivity. The aim of this study was to find a practical approach to perform automated Sanger DNA sequencing in clinical laboratories for validation of the DNA tests for these three infectious agents.
A crude proteinase K digestate of 5% of the cells collected in a liquid-based cervicovaginal cytology specimen was used for the detection of DNA molecules specific for HPV, C trachomatis and N gonorrhoeae, and for preparation of materials suitable for direct automated DNA sequencing. Several sets of commercially available polymerase chain reaction (PCR) primers were used to prepare nested PCR amplicons for direct DNA sequencing.
Some variants of HPV-16 and HPV-31 were found to share an at least 34-base long sequence homology downstream of the GP5+ binding site, and all HPV-6 and HPV-11 variants shared an upstream 34-base sequence including part of the GP5+ primer. Accurate HPV genotyping frequently required more than 34-bases for sequence alignments to distinguish some of the HPV genotype variants with closely related sequences in this L1 gene hypervariable region. Using the automated Sanger DNA sequencing method for parallel comparative studies on split samples and to retest the residues of samples previously tested positive for C trachomatis and/or for N gonorrhoeae, we also found false-negative and false-positive results as reported by two commercial nucleic acid test kits.
Identification of a signature DNA sequence by the automated Sanger method is useful for validation of HPV genotyping and for molecular testing of C trachomatis and N gonorrhoeae in liquid-based cervicovaginal Papanicolaou (Pap) cytology specimens for clinical laboratories with experience in molecular biology to increase the specificity of these DNA-based tests. However, even a highly specific test for high-risk HPV genotyping may have unacceptably low positive predictive values for precancer lesion in populations with a low cervical cancer prevalence rate.
PMCID: PMC2672071  PMID: 19358733
9.  Interaction between polymorphisms of the Human Leukocyte Antigen and HPV-16 Variants on the risk of invasive cervical cancer 
BMC Cancer  2008;8:246.
Persistent infection with oncogenic types of human papillomavirus (HPV) is the major risk factor for invasive cervical cancer (ICC), and non-European variants of HPV-16 are associated with an increased risk of persistence and ICC. HLA class II polymorphisms are also associated with genetic susceptibility to ICC. Our aim is to verify if these associations are influenced by HPV-16 variability.
We characterized HPV-16 variants by PCR in 107 ICC cases, which were typed for HLA-DQA1, DRB1 and DQB1 genes and compared to 257 controls. We measured the magnitude of associations by logistic regression analysis.
European (E), Asian-American (AA) and African (Af) variants were identified. Here we show that inverse association between DQB1*05 (adjusted odds ratio [OR] = 0.66; 95% confidence interval [CI]: 0.39–1.12]) and HPV-16 positive ICC in our previous report was mostly attributable to AA variant carriers (OR = 0.27; 95%CI: 0.10–0.75). We observed similar proportions of HLA DRB1*1302 carriers in E-P positive cases and controls, but interestingly, this allele was not found in AA cases (p = 0.03, Fisher exact test). A positive association with DRB1*15 was observed in both groups of women harboring either E (OR = 2.99; 95% CI: 1.13–7.86) or AA variants (OR = 2.34; 95% CI: 1.00–5.46). There was an inverse association between DRB1*04 and ICC among women with HPV-16 carrying the 350T [83L] single nucleotide polymorphism in the E6 gene (OR = 0.27; 95% CI: 0.08–0.96). An inverse association between DQB1*05 and cases carrying 350G (83V) variants was also found (OR = 0.37; 95% CI: 0.15–0.89).
Our results suggest that the association between HLA polymorphism and risk of ICC might be influenced by the distribution of HPV-16 variants.
PMCID: PMC2546426  PMID: 18721466
10.  Intratype variation in 12 human papillomavirus types: a worldwide perspective. 
Journal of Virology  1996;70(5):3127-3136.
In this study, we have examined intratype human papillomavirus (HPV) sequence variation in a worldwide collection of cervical specimens. Twelve different HPV types including HPV-18, HPV-33, HPV-35, HPV-39, HPV-45, HPV-51, HPV-52, HPV-58, HPV-59, HPV-68 (ME180), MM9/PAP238A (recently designated HPV-73), and a novel partial genomic HPV sequence designated MM4/Wl3B were analyzed in this study. Cervical specimens were collected as part of epidemiological investigations conducted in New Mexico and an international study of invasive cervical cancer (IBSCC). Specimens from several countries including Argentina, Brazil, Bolivia, Benin, Cuba, Colombia, Chile, Germany, Mali, Panama, Paraguay, Spain, Algeria, Uganda, Guinea, Tanzania, Indonesia, Philippines, Thailand, and the United States were evaluated. Specimen DNAs were subjected to amplification with the MY09/11 L1 consensus PCR system. The PCR products were cloned, and an approximately 410-bp region in the L1 open reading frame was sequenced from 146 specimens (approximately 60,000 bp). Within a single HPV type, nucleotide diversity varied between 0.2 and 2.9% (i.e., between any pair of variants) and the majority of nucleotide changes were synonymous (amino acid conserving). These data provide information pertinent to HPV diagnostic probe development and are potentially relevant to future rational vaccine strategies. Similarly, amino acid diversity varied between 0 and 5.1%. Some of these amino acid changes may represent markers of intertype evolutionary relationships. Presuming that HPVs have evolved under the same constraints as their corresponding hosts, the limited genetic diversity observed for all HPVs studied to date may reflect an evolutionary bottleneck occurring in both virus and host populations.
PMCID: PMC190175  PMID: 8627792
11.  Denaturing High-Performance Liquid Chromatography for Detecting and Typing Genital Human Papillomavirus 
Journal of Clinical Microbiology  2003;41(12):5563-5571.
Human papillomaviruses (HPVs) are important in the development of human cancers, including cervical and oral tumors. However, most existing methods for HPV typing cannot routinely distinguish among the more than 100 distinct types of HPV or the natural HPV intratypic variants that have also been documented. To address this problem, we developed a novel method, general primer-denaturing high-performance liquid chromatography (GP-dHPLC), for the detection and typing of genital HPV using an automated 96-well plate format. GP-dHPLC uses general primer PCR (GP-PCR) to amplify the viral DNA and then analyzes the GP-PCR products by denaturing high-performance liquid chromatography (dHPLC). A number of different primer pairs with homology to most known genital HPV types were tested, and the L1C1-L1C2M pair specific for the L1 region of the viral genome was chosen. A set of HPV standard control patterns, consisting of those for HPV types 16, 18, 31, 33, 39, 45, 51, 52, 56, 58, 59, 6, and 11, was established for genital HPV typing. One hundred eighty-six frozen and formalin-fixed cervical cancer tissue samples were analyzed for the presence of HPV and the HPV type by this method, and 95.8% of them were found to contain HPV DNA. GP-dHPLC accurately discriminated among HPV variants that differed by as little as one nucleotide. Several new variants of HPV types 16, 18, 39, 45, 52, and 59 were identified. Moreover, multiple HPV infections were detected in 26.6% of the samples. Our results indicate that HPV typing by GP-dHPLC permits discrimination of common genital HPV types, detection of multiple HPV infections, and identification of HPV variants in clinical samples.
PMCID: PMC309016  PMID: 14662941
12.  Oncogenic Human Papillomavirus (HPV) Type Distribution and HPV Type 16 E6 Variants in Two Spanish Population Groups with Different Levels of HPV Infection Risk 
Journal of Clinical Microbiology  2006;44(4):1428-1434.
The aim of this study is to determine oncogenic human papillomavirus (HPV) types and HPV type 16 (HPV16) variant distribution in two Spanish population groups, commercial sex workers and imprisoned women (CSW/IPW) and the general population. A multicenter cross-sectional study of 1,889 women from five clinical settings in two Spanish cities was conducted from May to November 2004. Oncogenic HPV infection was tested by an Hybrid Capture II (HC2) test, and positive samples were genotyped by direct sequencing using three different primer sets in L1 (MY09/11 and GP5+/GP6+) and E6/E7. HPV16 variants were identified by sequencing the E6, E2, and L1 regions. Four hundred twenty-five samples were positive for the HC2 test, 31.5% from CSW/IPW and 10.7% from the general population. HPV16 was the most frequent type. Distinct profiles of oncogenic HPV type prevalence were observed across the two populations. In order of decreasing frequency, HPV types 16, 31, 58, 66, 56, and 18 were most frequent in CSW/IPW women, and types 16, 31, 52, 68, 51, and 53 were most frequent in the general population. We analyzed HPV16 intratype variants, and a large majority (78.7%) belonged to the European lineage. AA variants were detected in 16.0% of cases. African variants belonging to classes Af1 (4.0%) and Af2 (1.3%) were detected. Different HPV types and HPV16 intratype variants are involved in oncogenic HPV infections in our population. These results suggest that HPV type distribution differs in CSW/IPW women and in the general population, although further analysis is necessary.
PMCID: PMC1448654  PMID: 16597872
13.  Integrated Human Papillomavirus Type 16 Is Frequently Found in Cervical Cancer Precursors as Demonstrated by a Novel Quantitative Real-Time PCR Technique 
Journal of Clinical Microbiology  2002;40(3):886-891.
In contrast to cervical cancer, integration of human papillomavirus (HPV) DNA into the host genome has been considered a rare event in cancer precursor lesions (cervical intraepithelial neoplasia [CIN]). With our new real-time PCR method, we demonstrated that integrated HPV type 16 (HPV16) is already present in CIN lesions. The physical state of HPV16 and the viral load were simultaneously detected. A unique region of the E2 open reading frame (ORF) that is most often deleted during HPV16 integration is targeted by one set of PCR primers and a probe, and another set targets the E6 ORF. In episomal form, both targets should be equivalent, while in integrated form, the copy numbers of E2 would be less than those of E6. The method was tested with DNAs from 31 cervical lesions (non-CIN to CINIII) from 24 women prospectively followed up for 10 years. This report presents viral load and integration results from the largest series of CIN lesions described to date. Only one sample contained exclusively episomal HPV16 DNA, and this lesion regressed spontaneously. Samples from another patient, with only integrated HPV16, rapidly progressed from CINI to CINIII in 2 years. In all other patients, episomal and integrated forms of HPV16 DNA were found to coexist. Rapid progression of the CIN lesions was closely associated with a heavy load of integrated HPV16. Thus, the method described here is a very sensitive tool with which to assess the physical state of HPV, which is useful in predicting disease progression.
PMCID: PMC120275  PMID: 11880410
14.  HPV frequency in penile carcinoma of Mexican patients: important contribution of HPV16 European variant 
The role of human papillomavirus (HPV) infection in penile carcinoma (PeC) is currently reported and about half of the PeC is associated with HPV16 and 18. We used a PCR-based strategy by using HPV general primers to analyze 86 penile carcinomas paraffin-embedded tissues. Some clinical data, the histological subtype, growth pattern, and differentiation degree were also collected. The amplified fragments were then sequenced to confirm the HPV type and for HPV16/18 variants. DNA samples were also subjected to relative real time PCR for hTERC gene copy number. Some clinical data were also collected. Global HPV frequency was 77.9%. Relative contributions was for HPV16 (85%), 31 (4.4%), 11 (4.4%), 58, 33, 18, and 59 (1.4% each one). Sequence analysis of HPV16 identified European variants and Asian-American (AAb-c) variants in 92% and in 8% of the samples, respectively. Furthermore hTERC gene amplification was observed in only 17% of the cases. Our results suggest that some members of HPV A9 group (represented by HPV16, 58, and 31) are the most frequent among PeC patients studied with an important contribution from HPV16 European variant. The hTERC gene amplification could be poorly related to penile epithelial tissue.
PMCID: PMC3693207  PMID: 23826423
HPV; penile carcinoma; México
15.  Use of multiple PCR primer sets for optimal detection of human papillomavirus. 
Journal of Clinical Microbiology  1996;34(9):2095-2100.
Using multiple PCR primer sets, we tried to optimize the detection of human papillomavirus (HPV) in DNA samples isolated from 361 frozen biopsy specimens from patients with invasive cervical carcinomas. The HPVs detected were placed into three distinct groups, including group I/Inex at Telelab (Skien, Norway) and group Ineg and group II at the Norwegian Radium Hospital (Oslo, Norway). The consensus primer sets were Oli-1b-oli-2i, My09-My11, Gp5-Gp6, and Gp(5+)-Gp6+ from the HPV L1 gene and CpI-CpIIG from the E1 gene. Using these consensus primers together with the type-specific primers from E6-E7, we found that 355 patients (98%) were HPV positive. Type-specific primers for HPV types 11, 16, 18, 31, 33, and 35 detected more HPV-infected patients than the most sensitive consensus primer set, while the three consensus primer sets My, Gp/Gp+, and Cp together detected more HPV-positive patients than the type-specific primers. Testing of sensitivity of the PCR with SiHa cells serially diluted in lymphocytes (HPV-negative cells) indicated a detection limit of 6,300 HPV type 16 DNA copies with consensus primers (My, Gp+, and Cp) and 126 original HPV type 16 DNA copies with type-specific primers. Comparison of the amplification results for consensus L1 primers and type-specific E6-E7 primers indicated the presence of L1 deletions in 23 of 56 samples. The conclusion is that in PCR detection systems, multiple consensus primers and type-specific primers should be used in order to detect all patients harboring HPV.
PMCID: PMC229196  PMID: 8862564
16.  Human Papillomavirus Type 16 Genetic Variants: Phylogeny and Classification Based on E6 and LCR 
Journal of Virology  2012;86(12):6855-6861.
Naturally occurring genetic variants of human papillomavirus type 16 (HPV16) are common and have previously been classified into 4 major lineages; European-Asian (EAS), including the sublineages European (EUR) and Asian (As), African 1 (AFR1), African 2 (AFR2), and North-American/Asian-American (NA/AA). We aimed to improve the classification of HPV16 variant lineages by using a large resource of HPV16-positive cervical samples collected from geographically diverse populations in studies on HPV and/or cervical cancer undertaken by the International Agency for Research on Cancer. In total, we sequenced the entire E6 genes and long control regions (LCRs) of 953 HPV16 isolates from 27 different countries worldwide. Phylogenetic analyses confirmed previously described variant lineages and subclassifications. We characterized two new sublineages within each of the lineages AFR1 and AFR2 that are robustly classified using E6 and/or the LCR. We could differentiate previously identified AA1, AA2, and NA sublineages, although they could not be distinguished by E6 alone, requiring the LCR for correct phylogenetic classification. We thus provide a classification system for HPV16 genomes based on 13 and 32 phylogenetically distinguishing positions in E6 and the LCR, respectively, that distinguish nine HPV16 variant sublineages (EUR, As, AFR1a, AFR1b, AFR2a, AFR2b, NA, AA1, and AA2). Ninety-seven percent of all 953 samples fitted this classification perfectly. Other positions were frequently polymorphic within one or more lineages but did not define phylogenetic subgroups. Such a standardized classification of HPV16 variants is important for future epidemiological and biological studies of the carcinogenic potential of HPV16 variant lineages.
PMCID: PMC3393538  PMID: 22491459
17.  Worldwide Genomic Diversity of the High-Risk Human Papillomavirus Types 31, 35, 52, and 58, Four Close Relatives of Human Papillomavirus Type 16 
Journal of Virology  2005;79(21):13630-13640.
Among the more than one hundred formally described human papillomavirus (HPV) types, 18 are referred to as high-risk HPV types due to their association with anogenital cancer. Despite pathogenic similarities, these types form three remotely related taxonomic groups. One of these groups is called HPV species 9 and is formed by HPV-16, the most common and best-studied type, together with HPV-31, -33, -35, -52, -58, and -67. Previous worldwide comparisons of HPV-16 samples showed about 2% nucleotide diversity between isolates, which were subsequently termed variants. The distribution of divergent variants has been found to correlate frequently with the geographic origin and the ethnicity of the infected patients and led to the concept of unique African, European, Asian, and Native American HPV-16 variants. In the current study, we address the question of whether geography and ethnicity also correlate with sequence variations found for HPV-31, -35, -52, and -58. This was done by sequencing the long control region in samples derived from Europe, Asia, and Africa, and from immigrant populations in North and South America. We observed maximal divergence between any two variants within each of these four HPV types ranging from 1.8 to 3.6% based on nucleotide exchanges and, occasionally, on insertions and deletions. Similar to the case with HPV-16, these mutations are not random but indicate a relationship between the variants in form of phylogenetic trees. An interesting example is presented by a 16-bp insert in select variants of HPV-35, which appears to have given rise to additional variants by nucleotide exchanges within the insert. All trees showed distinct phylogenetic topologies, ranging from dichotomic branching in the case of HPV-31 to star phylogenies of the other three types. No clear similarities between these types or between these types and HPV-16 exist. While variant branches in some types were specific for Europe, Africa, or East Asia, none of the four trees reflected human evolution and spread to the extent illustrated by HPV-16. One possible explanation is that the rare HPV types that we studied spread and thereby diversified more slowly than the more abundant HPV-16 and may have established much of today's variant diversity already before the worldwide spread of humans 100,000 years ago. Most variants had prototypic amino acid sequences within the E6 oncoprotein and a segment of the L1 capsid protein. Some had one, two, or three amino acid substitutions in these regions, which might indicate biological and pathogenic diversity between the variants of each HPV type.
PMCID: PMC1262609  PMID: 16227283
18.  Phylogenetic analysis of 48 papillomavirus types and 28 subtypes and variants: a showcase for the molecular evolution of DNA viruses. 
Journal of Virology  1992;66(10):5714-5725.
Papillomaviruses are attractive models for studying the molecular evolution of DNA viruses because of the large number of isolates that exhibit genomic diversity and host species and tissue specificity. To examine their relationship, we selected two amino acid sequences, one of 52 residues within the early gene E1 and the other of 44 residues within the late gene L1, which allowed insertion- and deletion-free alignment of all accessible papillomavirus sequences. We constructed phylogenetic trees from the amino acid and corresponding nucleotide sequences from 28 published and 20 newly determined animal and human papillomavirus (HPV) genomic sequences by using distance matrix, maximum-likelihood, and parsimony methods. The trees agreed in all important topological aspects. One major branch with two clearly separated clusters contained 11 HPV types associated with epidermodysplasia verruciformis. A second major branch had all the papillomaviruses involved in genital neoplasia and, in distant relationship, the cutaneous papillomaviruses HPV type 2a (HPV-2a), HPV-3, and HPV-10 as well as the "butcher's" papillomavirus HPV-7 and two simian papillomaviruses. Four artiodactyl (even-toed hoofed mammal) papillomaviruses, the cottontail rabbit papillomavirus, and avian (chaffinch) papillomavirus type 1 formed a third major branch. Last, four papillomaviruses exhibited little affinity to any of these three branches; these were the cutaneous types HPV-1a, HPV-4, and HPV-41 and B-group bovine papillomavirus type 4. The phylogeny suggests that some branches of papillomavirus evolution are restricted to particular target tissues and that a general process of long-term papillomavirus-host coevolution has occurred. This latter hypothesis is still conjectural because of bias in the current data base for human types and the paucity of animal papillomavirus sequences. The comparison of evolutionary distances for the most closely related types with those of 28 subtypes and variants of HPV-2, HPV-5, HPV-6, HPV-16, and HPV-18 supports the type as a natural taxonomic unit, with subtypes and variants being expressions of minor intratype genomic diversity similar to that found in the natural populations of all biological species. An exception to this seems to be HPV-2c, which has an evolutionary distance from HPV-2a of the intertype magnitude and may eventually have to be regarded as a distinct type. We describe an experimental approach that estimates the taxonomic and phylogenetic positions of newly identified papillomaviruses without viral isolation and complete genomic sequencing.(ABSTRACT TRUNCATED AT 400 WORDS)
PMCID: PMC241446  PMID: 1326639
19.  Human Papillomavirus (HPV) genotype 18 variants in patients with clinical manifestations of HPV related infections in Bilbao, Spain 
Virology Journal  2012;9:258.
Human papillomavirus (HPV) variants differ in their biological and chemical properties, and therefore, may present differences in pathogenicity. Most authors classified variants based on the phylogenetic analysis of L1 region. Nevertheless, recombination in HPV samples is becoming a usual finding and thus, characterizing genetic variability in other regions should be essential.
We aimed to characterize the genetic variability of HPV 18 in 5 genomic regions: E6, E7, E4, L1 and the Upstream Regulatory Region (URR), working with both single infection and multiple HPV infection samples. Furthermore, we aimed to assess the prevalence of HPV 18 variants in our region and look for possible existence of recombination as well as analyze the relationship between these variants and the type of lesion.
From 2007 to 2010, Clinical Microbiology and Infection Control Department analyzed 44 samples which were positive for HPV 18. Genetic variability was determined in PCR products and variants were assigned to European, Asian-amerindian or African lineage. Recombination and association of variants with different types of lesion was studied.
Genetic analysis of the regions revealed a total of 56 nucleotide variations. European, African and Asian-amerindian variants were found in 25/44 (56.8%), 10/44 (22.7%) and 5/44 (11.4%) samples, respectively. We detected the presence of recombinant variants in 2/44 (4.5%) cases. Samples taken from high-grade squamous intraepithelial lesions (H-SIL) only presented variants with specific-african substitutions.
Multiple HPV infection, non-european HPV variants prevalence and existence of recombination are considered risk factors for HPV persistence and progression of intraepithelial abnormalities, and therefore, should be taken into consideration in order to help to design and optimize diagnostics protocols as well as improve epidemiologic studies.
Our study is one of the few studies in Spain which analyses the genetic variability of HPV18 and we showed the importance of characterizing more than one genomic region in order to detect recombination and classify HPV variants properly.
PMCID: PMC3495774  PMID: 23121839
Human papillomavirus infection; Genotype 18; Variants; Recombination; Multiple infection
20.  Human Papillomavirus Type 16 Variant Analysis of E6, E7, and L1 Genes and Long Control Region in Biopsy Samples from Cervical Cancer Patients in North India▿  
Journal of Clinical Microbiology  2008;46(3):1060-1066.
High-risk human papillomaviruses (HPVs), particularly HPV types 16 and 18 (HPV-16 and HPV-18, respectively), play a cardinal role in the etiology of cervical cancer. The most prevalent type, HPV-16, shows intratypic sequence variants that are known to differ in oncogenic potential and geographic distribution. This study was designed to analyze sequence variations in E6, E7, and L1 genes and the LCR (for long control region) of HPV-16 in cervical cancer patients to identify the most prevalent and novel HPV-16 variants and to correlate them with the severity of the disease. Cervical biopsies from 60 HPV-16-positive cancer cases were analyzed by PCR and DNA sequencing. The most frequently observed variations were T350G (100%) in E6, T789C (87.5%) in E7, A6695C (54.5%) in L1, and G7521A (91.1%) in the LCR. In addition, only one novel variant (T527A) in E6 and four new variants each in L1 (A6667C, A6691G, C6906T, and A6924C) and in the LCR (C13T, A7636C, C7678T, and G7799A) were identified. While E7 was found to be highly conserved, the variant 350G of E6 was the most prevalent in all of the histopathological grades. The majority of LCR variants were found at the YY1 transcription factor binding sites. Interestingly, a complete absence of the Asian lineage and a high prevalence of European lineages in E6, E7, L1, and the LCR (85, 86.7, 67.7, and 63.3%, respectively) indicate a possible epidemiological linkage between Europe and India with regard to the dissemination of HPV-16 infections in India.
PMCID: PMC2268386  PMID: 18199779
21.  Analysis by Multiplex PCR of the Physical Status of Human Papillomavirus Type 16 DNA in Cervical Cancers 
Journal of Clinical Microbiology  1999;37(11):3514-3517.
Integration of human papillomavirus (HPV) DNA occurs early in cancer development and is an important event in malignant transformation of cervical cancer. Integration of HPVs preferentially disrupts or deletes the E2 open reading frame, which results in the loss of its expression. The preferential disruption of the E2 gene causes the absence of the E2 gene sequences in the PCR product following integration. Twenty-two carcinomas positive for HPV type 16 (HPV-16) DNA were first tested for the disruption of the E2 gene by PCR. A specific fragment of the E2 gene was not amplified in 10 cases, suggesting integration of HPV DNA into the host genome. Next, multiplex PCR for the HPV E2 and E6 genes was carried out in the remaining 12 cases. Copy numbers of both genes should be equivalent in episomal forms, while the E2 gene copy number will be smaller than that for E6 following the preferential disruption of the E2 gene in concominant forms. Although relative ratios of HPV E2 to E6 PCR products (E2/E6 ratios) ranged from 1.40 to 2.34 in 10 of 12 cases, multiplex PCR products from 2 cases displayed extremely low ratios of 0.69 and 0.61. Southern blot hybridization with an HPV-16 probe revealed that only in these two cases was both episomal and integrated HPV DNA being carried simultaneously. Thus, multiplex PCR for the E2 and E6 genes of HPV-16 DNA following PCR for the E2 gene can distinguish the pure episomal form from a mixed form of episomal and integrated HPV DNA. Clinical application of this technique will help researchers to understand the implication of the integration of HPV DNA for cervical carcinogenesis and cervical cancer progression.
PMCID: PMC85682  PMID: 10523544
22.  Sequence Variation Analysis of HPV-18 Isolates in Southwest China 
PLoS ONE  2013;8(2):e56614.
Intratypic variations of HPV-18 are known to differ in the persistence of the infection, frequency of carcinogenesis and the progression of precursor lesions to advanced cervical cancer. This study was designed to analyze sequence variations of HPV-18 isolates in order to discover novel HPV-18 variants and to evaluate the variations among infected women in southwest China. Cervical biopsies from 56 HPV-18-positive women with cervical neoplasia were assayed by PCR amplification and sequencing of all eight genes (E1, E2, E4, E5, E6, E7, L1, L2) of the HPV-18 genome. The most frequently observed variation was a C to G transversion at nucleotide 287 of E6, which was found in 48.2% of samples. Analysis of E7 revealed only one specimen as having sequence variations. In addition, we have identified several novel variations: A551C in E6, G6906A in L1, and C4915T and C5147A in L2. The mutations in E6 and L2 are silent, while the E7 mutation results in a single amino acid change. This study complements and expands on previous descriptions of HPV-18 variants. The sequence variation data presented here provides a foundation for future research on HPV-induced oncogenesis and may prove valuable for developing diagnostic probes and in the design of HPV vaccines for targeted populations.
PMCID: PMC3581518  PMID: 23451059
23.  High prevalence of human papillomavirus infection in American Indian women of the Northern Plains 
Gynecologic oncology  2007;107(2):236-241.
Cervical cancer is the leading gynecological malignancy worldwide, and the incidence of this disease is very high in American Indian women. Infection with the Human Papillomavirus (HPV) is responsible for more than 95% of cervical squamous carcinomas. Therefore, the main objective of this study was to analyze oncogenic HPV infections in American Indian women residing in the Northern Plains.
Cervical samples were collected from 287 women attending a Northern Plains American Indian reservation outpatient clinic. DNA was extracted from the cervical samples and HPV specific DNA were amplified by polymerase chain reaction (PCR) using the L1 consensus primer sets. The PCR products were hybridized with the Roche HPV Line Blot assay for HPV genotyping to detect 27 different low and high-risk HPV genotypes. The chi-square test was performed for statistical analysis of the HPV infection and cytology diagnosis data.
Of the total 287 patients, 61 women (21.25%) tested positive for HPV infection. Among all HPV-positive women, 41 (67.2%) were infected with high-risk HPV types. Of the HPV infected women, 41% presented with multiple HPV genotypes. Additionally, of the women infected with oncogenic HPV types, 20 (48.7%) were infected with HPV 16 and 18 and the remaining 21 (51.3%) were infected with other oncogenic types (i.e., HPV59, 39, 73). Women infected with oncogenic HPV types had significantly higher (p=0.001) abnormal Papanicolaou smear tests (Pap test) compared to women who were either HPV negative or positive for non-oncogenic HPV types. The incidence of HPV infection was inversely correlated (p<0.05) with the age of the patients, but there was no correlation (p=0.33) with seasonal variation.
In this study, we observed a high prevalence of HPV infection in American Indian women residing on Northern Plains Reservations. In addition, a significant proportion of the oncogenic HPV infections were other than HPV16 and 18.
PMCID: PMC2396448  PMID: 17659767
Human Papillomavirus; American Indian; Northern Plains; Cervical cancer; Cervical cancer diagnosis
24.  Single-tube multiplex PCR using type-specific E6/E7 primers and capillary electrophoresis genotypes 21 human papillomaviruses in neoplasia 
Human papillomavirus (HPV) E6/E7 type-specific oncogenes are required for cervical carcinogenesis. Current PCR protocols for genotyping high-risk HPV in cervical screening are not standardized and usually use consensus primers targeting HPV capsid genes, which are often deleted in neoplasia. PCR fragments are detected using specialized equipment and extra steps, including probe hybridization or primer extension. In published papers, analytical sensitivity is typically compared with a different protocol on the same sample set.
A single-tube multiplex PCR containing type-specific primers was developed to target the E6/E7 genes of two low-risk and 19 high-risk genotypes (HPV6, 11 and 16, 18, 26, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, 70, 73 and 82) and the resulting short fragments were directly genotyped by high-resolution fluorescence capillary electrophoresis.
The method was validated using long oligonucleotide templates, plasmid clones and 207 clinical samples of DNA from liquid-based cytology, fresh and formalin-fixed specimens and FTA Microcards® imprinted with cut tumor surfaces, swabbed cervical cancers or ejected aspirates from nodal metastases of head and neck carcinomas. Between one and five long oligonucleotide targets per sample were detected without false calls. Each of the 21 genotypes was detected in the clinical sample set with up to five types simultaneously detected in individual specimens. All 101 significant cervical neoplasias (CIN 2 and above), except one adenocarcinoma, contained E6/E7 genes. The resulting genotype distribution accorded with the national pattern with HPV16 and 18 accounting for 69% of tumors. Rare HPV types 70 and 73 were present as the sole genotype in one carcinoma each. One cervical SCC contained DNA from HPV6 and 11 only. Six of twelve oropharyngeal cancer metastases and three neck metastases of unknown origin bore E6/E7 DNA; all but one were HPV16. One neck aspirate contained atypical squames with HPV26.
Analytical sensitivity in dilute plasmid mixes was variable.
A primer-rich PCR readily detects the E6/E7 oncogenes of 21 HPV types in cellular and fixed tissue specimens. The method is straightforward, robust and reproducible and avoids post-PCR enzymatic and hybridization steps while detecting HPV with high clinical sensitivity in significant HPV-related neoplasia regardless of specimen type.
PMCID: PMC3035480  PMID: 21241508
25.  Development and Clinical Evaluation of a Highly Sensitive PCR-Reverse Hybridization Line Probe Assay for Detection and Identification of Anogenital Human Papillomavirus 
Journal of Clinical Microbiology  1999;37(8):2508-2517.
Human papillomavirus (HPV) can be detected by amplification of viral DNA. A novel PCR primer set generating a short PCR fragment (SPF PCR) was used for amplification of a fragment of only 65 bp from the L1 region and permitted ultrasensitive detection of a broad spectrum of HPV genotypes. The intra- and intertypic sequence variations of the 22-bp interprimer region of this amplimer were studied. Among 238 HPV sequences from GenBank and clinical specimens, HPV genotypes were correctly identified based on the 22-bp sequence in 232 cases (97.2%). Genotype-specific probes for HPV genotypes 6, 11, 16, 18, 31, 33 to 35, 39, 40, 42 to 45, 51 to 54, 56, 58, 59, 66, 68, 70, and 74 were selected, and a reverse hybridization line probe assay (LiPA) (the INNO-LiPA HPV prototype research assay) was developed. This LiPA permits the use of amplimers generated by the SPF as well as the MY 09/11 primers. The assay was evaluated with a total of 1,354 clinical specimens, comprising cervical scrapes (classifications ranging from normal cytology to severe dyskaryosis) and formalin-fixed, paraffin-embedded cervical carcinoma samples. LiPA results were highly concordant with sequence analysis of the SPF amplimer, genotype-specific PCR, and sequence analysis of amplimers generated by MY 09/11 primers. The sensitivity of the SPF primers was higher than that of the GP5+/6+ primers over a broad range of HPV types, especially when multiple HPV genotypes were present. In conclusion, the SPF LiPA method allows extremely sensitive detection of HPV DNA as well as reliable identification of HPV genotypes in both cervical smears and paraffin-embedded materials.
PMCID: PMC85270  PMID: 10405393

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