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1.  Cell cycle–related genes as modifiers of age of onset of colorectal cancer in Lynch syndrome: a large-scale study in non-Hispanic white patients 
Carcinogenesis  2012;34(2):299-306.
Heterogeneity in age of onset of colorectal cancer in individuals with mutations in DNA mismatch repair genes (Lynch syndrome) suggests the influence of other lifestyle and genetic modifiers. We hypothesized that genes regulating the cell cycle influence the observed heterogeneity as cell cycle–related genes respond to DNA damage by arresting the cell cycle to provide time for repair and induce transcription of genes that facilitate repair. We examined the association of 1456 single nucleotide polymorphisms (SNPs) in 128 cell cycle–related genes and 31 DNA repair–related genes in 485 non-Hispanic white participants with Lynch syndrome to determine whether there are SNPs associated with age of onset of colorectal cancer. Genotyping was performed on an Illumina GoldenGate platform, and data were analyzed using Kaplan–Meier survival analysis, Cox regression analysis and classification and regression tree (CART) methods. Ten SNPs were independently significant in a multivariable Cox proportional hazards regression model after correcting for multiple comparisons (P < 5×10–4). Furthermore, risk modeling using CART analysis defined combinations of genotypes for these SNPs with which subjects could be classified into low-risk, moderate-risk and high-risk groups that had median ages of colorectal cancer onset of 63, 50 and 42 years, respectively. The age-associated risk of colorectal cancer in the high-risk group was more than four times the risk in the low-risk group (hazard ratio = 4.67, 95% CI = 3.16–6.92). The additional genetic markers identified may help in refining risk groups for more tailored screening and follow-up of non-Hispanic white patients with Lynch syndrome.
PMCID: PMC3564440  PMID: 23125224
2.  Incidence and Risk of Treatment-Related Mortality with mTOR Inhibitors Everolimus and Temsirolimus in Cancer Patients: A Meta-Analysis 
PLoS ONE  2013;8(6):e65166.
Two novel mammalian targets of rapamycin (mTOR) inhibitors everolimus and temsirolimus are now approved by regulatory agencies and have been widely investigated among various types of solid tumors, but the risk of fatal adverse events (FAEs) with these drugs is not well defined.
We searched PubMed, EMBASE, and Cochrane library databases for relevant trials. Eligible studies included prospective phase II and III trials evaluating everolimus and temsirolimus in patients with all malignancies and data on FAEs were available. Statistical analyses were conducted to calculate the summary incidence, RRs and 95% confidence intervals (CIs) by using either random effects or fixed effect models according to the heterogeneity of the included studies.
A total of 3322 patients with various advanced solid tumors from 12 trials were included. The overall incidence of mTOR inhibitors associated FAEs was 1.8% (95%CI: 1.3–2.5%), and the incidences of everolimus related FAEs were comparable to that of temsirolimus (1.7% versus 1.8%). Compared with the controls, the use of mTOR inhibitors was associated with an increased risk of FAEs, with a RR of 3.24 (95%CI: 1.21–8.67, p = 0.019). On subgroup analysis, a non-statistically significant increase in the risk of FAEs was found according to different mTOR inhibitors, tumor types or controlled therapy. No evidence of publication bias was observed.
With the present evidence, the use of mTOR inhibitors seems to increase the risk of FAEs in patients with advanced solid tumors. More high quality trials are still needed to investigate this association.
PMCID: PMC3681778  PMID: 23785409
3.  Association between Single Nucleotide Polymorphisms in ERCC4 and Risk of Squamous Cell Carcinoma of the Head and Neck 
PLoS ONE  2012;7(7):e41853.
Excision repair cross-complementation group 4 gene (ERCC4/XPF) plays an important role in nucleotide excision repair and participates in removal of DNA interstrand cross-links and DNA double-strand breaks. Single nucleotide polymorphisms (SNPs) in ERCC4 may impact repair capacity and affect cancer susceptibility.
Methodology/Principal Findings
In this case-control study, we evaluated associations of four selected potentially functional SNPs in ERCC4 with risk of squamous cell carcinoma of the head and neck (SCCHN) in 1,040 non-Hispanic white patients with SCCHN and 1,046 cancer-free matched controls. We found that the variant GG genotype of rs2276466 was significantly associated with a decreased risk of SCCHN (OR = 0.69, 95% CI 0.50–0.96), and that the variant TT genotype of rs3136038 showed a borderline significant decreased risk with SCCHN (OR = 0.76, 95% CI: 0.58–1.01) in the recessive model. Such protective effects were more evident in oropharyngeal cancer (OR = 0.61, 95% CI: 0.40–0.92 for rs2276466; OR = 0.69, 95% CI: 0.48–0.98 for rs3136038). No significant associations were found for the other two SNPs (rs1800067 and rs1799798). In addition, individuals with the rs2276466 GG or with the rs3136038 TT genotypes had higher levels of ERCC4 mRNA expression than those with the corresponding wild-type genotypes in 90 Epstein-Barr virus-transformed lymphoblastoid cell lines derived from Caucasians.
These results suggest that these two SNPs (rs2276466 and rs3136038) in ERCC4 may be functional and contribute to SCCHN susceptibility. However, our findings need to be replicated in further large epidemiological and functional studies.
PMCID: PMC3407112  PMID: 22848636
4.  Association between a Functional Polymorphism (-1195T>C) in the IGFBP5 Promoter and Head and Neck Cancer Risk 
Head & neck  2010;33(5):650-660.
No studies have evaluated roles of insulin-like growth factor binding protein 5 (IGFBP-5) polymorphisms in risk of squamous cell carcinoma of the head and neck (SCCHN).
A hospital-based study of 1082 SCCHN patients and 1120 cancer-free controls was performed to investigate associations between two functional polymorphisms -1195T>C and -709G>C in the IGFBP5 promoter region and SCCHN risk.
We demonstrated that the transcription factor AP-1 differentially bound to T or C variants at -1195 in the promoter to regulate the IGFBP5 promoter activity and that the C variant genotypes were associated with deferential risk of late-stage SCCHN, compared with the TT genotype, particularly for HPV-unrelated sites (adjusted OR, 2.21; 95% CI, 1.19-4.11 for CC vs. TT).
The IGFBP5 -1195T>C polymorphism is functional and may potentially be a biomarker for susceptibility to late-stage SCCHN.
PMCID: PMC3023825  PMID: 20949447
IGFBP5; head neck cancer; TNM stage; polymorphism; association
5.  A novel functional DEC1 promoter polymorphism −249T>C reduces risk of squamous cell carcinoma of the head and neck 
Carcinogenesis  2010;31(12):2082-2090.
Human DEC1 (deleted in esophageal cancer 1) gene is located on chromosome 9q, a region frequently deleted in various types of human cancers, including squamous cell carcinoma of the head and neck (SCCHN). However, only one epidemiological study has evaluated the association between DEC1 polymorphisms and cancer risk. In this hospital-based case–control study, four potentially functional single-nucleotide polymorphisms −1628 G>A (rs1591420), −606 T>C [rs4978620, in complete linkage disequilibrium with −249T>C (rs2012775) and −122 G>A(rs2012566)], c.179 C>T p.Ala60Val (rs2269700) and 3′ untranslated region-rs3750505 as well as the TP53 tumor suppressor gene codon 72 (Arg72Pro, rs1042522) polymorphism were genotyped in 1111 non-Hispanic Whites SCCHN patients and 1130 age-and sex-matched cancer-free controls. After adjustment for age, sex and smoking and drinking status, the variant −606CC (i.e. −249CC) homozygotes had a significantly reduced SCCHN risk (adjusted odds ratio = 0.71, 95% confidence interval = 0.52–0.99) compared with the −606TT homozygotes. Stratification analyses showed that a reduced risk associated with the −606CC genotype was more pronounced in subgroups of non-smokers, non-drinkers, younger subjects (defined as ≤57 years), carriers of the TP53 Arg/Arg (rs1042522) genotype, patients with oropharyngeal cancer or late-stage SCCHN. Further in silico analysis revealed that the −249 T-to-C change led to a gain of a transcription factor-binding site. Additional functional analysis showed that the −249T-to-C change significantly enhanced transcriptional activity of the DEC1 promoter and the DNA–protein-binding activity. We conclude that the DEC1 promoter −249 T>C (rs2012775) polymorphism is functional, modulating susceptibility to SCCHN among non-Hispanic Whites.
PMCID: PMC2994282  PMID: 20935061
6.  The functional IGFBP7 promoter −418G>A polymorphism and Risk of Head and Neck Cancer 
Mutation research  2010;702(1):32-39.
Insulin-like growth factor binding protein 7 (IGFBP7) functions mostly independent of the IGF signaling pathway and acts as a tumor suppressor in multiple cancers, but roles of IGFBP7 genetic variants in cancer remains unknown. In a hospital-based study of 1,065 patients with squamous cell carcinoma of head and neck (SCCHN) and 1,112 cancer-free controls of non-Hispanic whites, we investigated associations between two putatively functional IGFBP7 promoter single nucleotide polymorphisms (SNPs) (−702G>C, rs11573014 and −418G>A, rs4075349) and SCCHN risk. A significantly lower SCCHN risk was observed in those subjects carrying −418AG (adjusted OR=0.82, 95% CI=0.67–0.99) and −418AG+AA (adjusted OR=0.82, 95% CI=0.69–0.99) genotypes than those carrying the −418GG genotype, but not for the −702G>C SNP. However, those subjects carrying two common homozygous genotypes of these two SNPs (−418GG and −702GG) had an increased risk (adjusted OR=1.21, 95% CI=1.00-0.1.46) than did those carrying variant genotypes (−418AG+AA and −702CG+CC). This increased risk was more evident in subgroups of never smokers and subjects with oral cancer. Further functional analysis showed that the IGFBP7 −418A allele had significantly higher promoter and DNA-protein binding activities than did the G allele, suggesting a tumor suppressor role of this allelic change in the SCCHN etiology. We conclude that the functional variant −418 G>C in the IGFBP7 promoter is associated with reduced risk of SCCHN, likely by enhancing the IGFBP7 promoter and DNA-protein binding activities. Larger studies are needed to validate our findings.
PMCID: PMC2939148  PMID: 20599521
IGFBP7; case-control study; tumor suppressor gene; head and neck cancer; promoter polymorphism
7.  Polymorphisms of Homologous Recombination Genes and Clinical Outcomes of Non-Small Cell Lung Cancer Patients Treated with Definitive Radiotherapy 
PLoS ONE  2011;6(5):e20055.
The repair of DNA double-strand breaks (DSBs) is the major mechanism to maintain genomic stability in response to irradiation. We hypothesized that genetic polymorphisms in DSB repair genes may affect clinical outcomes among non-small cell lung cancer (NSCLC) patients treated with definitive radio(chemo)therapy. We genotyped six potentially functional single nucleotide polymorphisms (SNPs) (i.e., RAD51 −135G>C/rs1801320 and −172G>T/rs1801321, XRCC2 4234G>C/rs3218384 and R188H/rs3218536 G>A, XRCC3 T241M/rs861539 and NBN E185Q/rs1805794) and estimated their associations with overall survival (OS) and radiation pneumonitis (RP) in 228 NSCLC patients. We found a predictive role of RAD51 −135G>C SNP in RP development (adjusted hazard ratio [HR] = 0.52, 95% confidence interval [CI], 0.31–0.86, P = 0.010 for CG/CC vs. GG). We also found that RAD51 −135G>C and XRCC2 R188H SNPs were independent prognostic factors for overall survival (adjusted HR = 1.70, 95% CI, 1.14–2.62, P = 0.009 for CG/CC vs. GG; and adjusted HR = 1.70; 95% CI, 1.02–2.85, P = 0.043 for AG vs. GG, respectively) and that the SNP-survival association was most pronounced in the presence of RP. Our study suggests that HR genetic polymorphisms, particularly RAD51 −135G>C, may influence overall survival and radiation pneumonitis in NSCLC patients treated with definitive radio(chemo)therapy. Large studies are needed to confirm our findings.
PMCID: PMC3102071  PMID: 21647442
8.  Polymorphisms in the SULF1 gene are associated with early age of onset and survival of ovarian cancer 
SULF1 (sulfatase 1) selectively removes the 6-O-sulphate group from heparan sulfate, changing the binding sites for extracellular growth factors. SULF1 expression has been reported to be decreased in various cancers, including ovarian cancer. We hypothesized that single nucleotide polymorphisms (SNPs) of SULF1 would impact clinicopathologic characteristics.
We genotyped five common (minor allele frequency>0.05) regulatory SNPs with predicted functionalities (rs2623047 G>A, rs13264163 A>G, rs6990375 G>A, rs3802278 G>A, and rs3087714 C>T) in 168 patients with primary epithelial ovarian cancer, using the polymerase chain reaction-restriction fragment length polymorphism method.
We found that rs2623047 G>A was significantly associated with an early age of onset of ovarian cancer in the G allele dose-response manner (P = 0.027; Ptrend = 0.007) and that rs2623047 GG/GA genotypes were associated with longer progression-free survival; rs6990375 G>A was also associated with the early age of onset in the A allele dose-response manner (P = 0.013; Ptrend= 0.009). The significant differences in age of disease onset persisted among carriers of haplotypes of rs2623047 and rs6990375 (P = 0.014; Ptrend = 0.004). In luciferase reporter gene assays, rs2623047 G allele showed a slightly higher promoter activity than the A allele in the SKOV3 tumorigenic cell line.
These findings suggest that genetic variations in SULF1 may play a role in ovarian cancer onset and prognosis. Further studies with large sample sizes and of the mechanistic relevance of SULF1 SNPs are warranted.
PMCID: PMC3025876  PMID: 21214932
9.  Genetic polymorphisms in the PTPN13 gene and risk of squamous cell carcinoma of head and neck 
Carcinogenesis  2009;30(12):2053-2058.
Fas-associated phosphatase-1 is encoded by the protein tyrosine phosphatase, non-receptor type 13 (PTPN13) gene and attributes to the resistance to Fas-mediated apoptosis in several tumors, including squamous cell carcinoma of the head and neck (SCCHN). However, no epidemiological studies have investigated the roles of PTPN13 polymorphisms in SCCHN risk. In this hospital-based case–control study of 1069 SCCHN patients and 1102 non-Hispanic white cancer-free controls, we evaluated the associations between three single-nucleotide polymorphisms c.4068 T>G F1356L (rs10033029), c.4566 A>G I1522M (rs2230600) and c.6241 T>G Y2081D (rs989902) located in the coding region of PTPN13 and SCCHN risk. We found that a significantly increased SCCHN risk was associated with the c.4566 I1522M GG genotype [odds ratio (OR), 1.89; 95% confidence interval (CI), 1.27–2.79] and c.6241 Y2081D GT genotype (OR, 1.26; 95% CI, 1.03–1.53) compared with the c.4566 I1522M AA and c.6241 Y2081D TT genotypes, respectively. Further stratified analyses showed that risk associated with the c.4566 I1522M GG genotype was more profound in the subgroups of young (≤57 years), males, never smokers, current drinkers and patients with pharyngeal cancer; that risk associated with c.6241 Y2081D GT genotype persisted in subgroups of old (>57 years), males, current drinkers and patients with pharyngeal and laryngeal cancers and that risk associated with c.6241 Y2081D GG genotype was borderline in patients with laryngeal cancer. In conclusion, polymorphisms in the PTPN13 coding region may be biomarkers for susceptibility to SCCHN in USA populations.
PMCID: PMC2792321  PMID: 19892796
10.  Genetic polymorphism of UL144 open reading frame of human cytomegalovirus DNA detected in colon samples from infants with Hirschsprung’s disease 
AIM: To explore the genetic diversities of UL144 open reading frame (ORF) of cytomegalovirus DNA detected in colon tissue from infants with Hirschsprung’s disease (HD) by sequencing UL144 DNA in 23 aganglionic colon tissue and 4 urine samples from 25 HD infants.
METHODS: Nest PCR was performed for amplification of the UL144 gene. The UL144 gene was analyzed with softwares, such as DNAclub, BioEdit, PROSITE database, and DNAstar.
RESULTS: The strains from HD patients were distributed among three genotypes of UL144: group 1A (64%), group 2 (24%), and group 3 (12%). The UL144 genotypes between strains from HD and control group were compared by chi square test (χ2 = 1.870, P = 0.393). Strains from the colon were sporadically distributed in UL144 genotypes.
CONCLUSION: There are genetic diversities of UL144 ORF in colon tissue of infants with HD. However, cytomegalovirus UL144 genotypes are not associated with clinical manifestations of HD.
PMCID: PMC4250863  PMID: 17708610
Hirschsprung’s disease; Cytomegalovirus; UL144 gene; Polymorphism

Results 1-10 (10)