ABSTRACT
<p><b>BACKGROUND</b>Several studies have evaluated the association between polymorphisms of thymidylate synthase (TS) and cancer risk in diverse populations but with conflicting results. By pooling the relatively small samples in each study, it is possible to evaluate the association using a meta-analysis.</p><p><b>METHODS</b>A comprehensive search was conducted to identify all case-control studies on TS on a 28-bp tandem repeats in 5'untranslated region (5'UTR) and a 6-bp insertion (ins) and deletion (del) mutation in 3'UTR of the gene and cancer risk. Meta-analysis was conducted using a fixed and random effect model.</p><p><b>RESULTS</b>Our meta-analysis on a total of 13 307 cancer cases and 18 226 control subjects from 37 published case-control studies showed no significant association between the risk of cancer and the 5'UTR 28-bp tandem repeats polymorphism (3R/3R vs. 2R/2R: OR = 1.06, 95%CI, 0.93 - 1.20) or the 3'UTR 6-bp ins/del polymorphism (del6/del6 vs. ins6/ins6: OR = 0.93, 95%CI, 0.81 - 1.08) with significant between-study heterogeneity. In the cancer type- and ethnic subgroup-stratification analyses, we did not find any association between TS polymorphisms and cancer risk either.</p><p><b>CONCLUSION</b>TS 5'UTR 28-bp tandem repeats and 3'UTR 6-bp ins/del polymorphisms may not be associated with cancer risk.</p>
Subject(s)
Humans , 3' Untranslated Regions , Genetics , 5' Untranslated Regions , Genetics , Case-Control Studies , Genetic Predisposition to Disease , Genetics , Neoplasms , Epidemiology , Genetics , Polymorphism, Genetic , Genetics , Tandem Repeat Sequences , Genetics , Thymidylate Synthase , GeneticsABSTRACT
Objective The 4-and 16-hydroxylated metabolites of estrogens have been implicated in carcinogenesis,whereas its 2-hydroxylated metabolites have been shown to have antiangiogenic effects.We aimed to examine whether the polymorphisms of catechol-O-methyltransferase(COMT)involved in the estrogen metabolism are associated with endometrial cancer risk.Methods Polymerase chain reaction- restrictive fragment length polymorphism(PCR-RFLP)analysis was used to study the variant allele frequency distributions of COMT Val158Met genetic polymorphism in a population based case-control study with 132 endometrial cancer cases and 110 controls.Odds ratios(OR)and 95% confidence intervals(CI) were estimated by unconditional logistic regression after adjustment for known or suspected risk factors for endometrial cancer.Results The most frequent genotype was COMT~(Val/Val)(47.2%,52/110)in control group and COMT~(Mal/Met)(58.3%,77/132)in endometrial cancer group.The difference between the two groups was of statistical significance(P