TS And MTHFR Gene Polymorphisms And Their Association With MRNA And Protein Expression In Yunnan Gastric CancerPatients

Objective:To investigate associations between polymorphisms and TS/MTHFRexpression. Meanwhile, the frequency of TS polymorphisms in gastric cancer patients were compared with those in healthy people in Yunnan region. The study may provide a possible explanation to the variant of response for5-FU efficacy in gastric cancer patients. Method:1.31Yunnan origin patients with gastric cancer who did not receive chemo radiotherapy were enrolled. Tumor tissues were collected during the surgery, and DNA was then isolated. Polymorphisms of3’UTR+/-6bp,5’UTR2R/3R and3R G>Cin TS gene were determined using PCR-RFLP. Genotype of677C>T and1298A>C in MTHFR gene were detected using TaqMan probe. We determined mRNA and protein expression by using Real-Time PCR and Western Blot respectively. Then the correlation between gene polymorphisms and expression was evaluated by ANOVA text.2.31patients with gastric cancer and another200healthy volunteers who are Yunnan origin were collected, and DNA was extracted from peripheral blood. Polymorphisms of3’UTR+/-6bp、5’UTR2R/3Rin TS gene were detected using PCR-RFLP. The frequencies of TS polymorphisms in gastric cancer patients were compared with those in healthy people in Yunnan region.Result:1. In all31patients, those with+/-6bp genotype have revealed higher expression of mRNA and protein than those with-/-6bp genotype(mRNA:P=0.043; protein: P=0.025).Reduced expression of TS protein was exhibited in2R/2R genotyped patients when compared with2R/3R and3R/3R genotype. In our research, other polymorphisms did not show significant differences in the mRNA and protein expression.(P>0.05)2. In the studied population, no difference was found between tumor and peripheral blood extracted DNA. The frequencies of+/-6bp alleles in TS gene of healthy population were33.5%and66.5%, and were25.8%and74.2%in gastric cancer patients.The frequencies of2R/3R alleles in TS gene of healthy populationwere15%and85%, and were22.6%and77.4%in gastric cancer patients. The frequencies of previous mentioned sites did not have statistical difference between Yunnan healthy population and gastric cancer patients in this study.Conclusion:Our research showed that higher mRNA and protein expression were associated with TS3’UTR+/-6bp and5’UTR3R genotype, which may affect the enzyme activities. The study suggested that frequencies of TS3’UTR+/-6bp,5’UTR2R/3R alleles did not have statistical difference between Yunnan healthy population and gastric cancer patients. Therefore, it can be assumed that the TS gene frequencies of healthy population which were obtained from a larger population, were more representative for patients with gastric cancer in Yunnan.