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author:("Feng, xinghua")
1.  Evaluation of Transported Dry and Wet Cervical Exfoliated Samples for Detection of Human Papillomavirus Infection▿  
Journal of Clinical Microbiology  2010;48(9):3068-3072.
We determined the feasibility of human papillomavirus (HPV) detection in cervical exfoliated cells collected as dry swab samples. Both dry cervical swab and specimen transport medium (STM) cervical swab samples were collected from 135 patients attending either colposcopy or women's clinics in Guayaquil, Ecuador, who had a cytology diagnosis within 6 months. HPV was detected by dot blot hybridization and genotyped by the liquid bead microarray assay (LBMA). Overall, 23.1% of dry samples were positive for any high-risk HPV types, and 24.6% of STM samples were positive for any high-risk HPV types. Of 125 paired samples, the type-specific high-risk HPV proportion positive agreement was 60.7% (kappa, 0.69; 95% confidence interval [CI], 0.53 to 0.82). Of six women with cytological evidence of invasive cervical cancer, high-risk HPV DNA was detected in three of their STM samples and in five of their dry samples. Dry samples were more likely to be insufficient for HPV testing than STM samples. Consistent with this observation, the amount of genomic DNA quantitated with the β-actin gene was almost 20 times lower in dry samples than in STM samples when detected by the real-time TaqMan assay; however, HPV DNA viral loads in dry samples were only 1.6 times lower than those in matched STM samples. We concluded that exfoliated cervical cells could be collected as dry swab samples for HPV detection.
PMCID: PMC2937663  PMID: 20610686
2.  Sequence Variation of Human Papillomavirus Type 16 and Measurement of Viral Integration by Quantitative PCR▿  
Journal of Clinical Microbiology  2008;47(3):521-526.
Given that the integration of human papillomavirus type 16 (HPV16) into the host genome occurs preferentially with the disruption of the E2 gene, a ratio of E2 to E7 gene copies is often used as a marker for integration. It is largely undetermined, however, whether ratio estimates are affected by HPV intratypic variations. We assembled four plasmid constructs, each containing a DNA fragment from an HPV16 European, Asian-American, African-1, or African-2 variant. These constructs and nine cervical swab samples were assayed by real-time PCR with two primer-probe sets for each gene: a specific set, fully complementary to the HPV16 prototype, and a degenerate set, incorporating degenerate bases at positions where nucleotides differed among the variants. The ratio of E2 to E7 gene copies for the European variant construct was close to 1, no matter which sets of primers and probes were used. While the ratios for the African-1 and Asian-American variant constructs remained close to 1 with the degenerate sets of primers and probes, the ratios were 0.36 and 2.57, respectively, with the specific sets of primers and probes. In addition, a nucleotide alteration at the position immediately following the 3′ end of the E2 forward primer binding site was found to be responsible for an underestimation of E2 gene copies for the African-2 variant construct. Similar patterns were found in nine cervical samples. In conclusion, mismatches between the primers and probes and their targets due to HPV16 intratypic variations would introduce errors in testing for integration; this situation can be sufficiently ameliorated by incorporating degenerate bases into the primers and probes.
PMCID: PMC2650947  PMID: 19116350
3.  Development and Evaluation of a Liquid Bead Microarray Assay for Genotyping Genital Human Papillomaviruses▿ †  
Journal of Clinical Microbiology  2009;47(3):547-553.
We developed a liquid bead microarray (LBMA) assay for genotyping genital human papillomaviruses (HPVs) based on the MY09-MY11-HMB01 PCR system and the reverse line blot (RLB) assay probe sequences. Using individual HPV plasmids, we were able to detect as few as 50 copies per reaction. In two separate retrospective studies, the LBMA assay was compared to the RLB assay and to the Hybrid Capture II (hc2) assay. Testing was performed without knowledge of other assay results. In the first study, 614 cervical swab samples (enriched for HPV infection) from 160 young women were tested for HPV DNA, and 360 (74.8%) type-specific HPV infections were detected by both assays, 71 (14.8%) by the LBMA assay only, and 50 (10.4%) by the RLB assay only. Type-specific agreement for the two assays was excellent (99.1%; kappa = 0.85; 95% confidence interval [95% CI], 0.82 to 0.88). Samples with discrepant LBMA and RLB test results tended to have low viral loads by a quantitative type-specific PCR assay. In the second study, cervical swab samples from 452 women (including 54 women with histologically confirmed cervical-intraepithelial neoplasia grade 2 or worse [≥CIN2]) were tested initially by the hc2 and subsequently by the LBMA assay. The estimated sensitivities for ≥CIN2 were similar for the LBMA and hc2 assays (98.4% [95% CI, 95.0 to 100%] and 95.6% [95% CI, 89.2 to 100%], respectively). The percentages of negative results among 398 women without ≥CIN2 were similar for the LBMA and hc2 assays (45% and 50%, respectively). The repeat test reproducibility for 100 samples was 99.1% (kappa = 0.92; 95% CI, 0.90 to 0.95). We conclude that the new LBMA assay will be useful for clinical and epidemiological research.
PMCID: PMC2650937  PMID: 19144800

Results 1-3 (3)