Effect of thymidylate synthase gene polymorphism on the response to chemotherapy and clinical outcome of non-small cell lung cancer patients

Association Between Genetic Polymorphisms In TYMS And Glioma Risk In Chinese Patients: A Case-Control Study

Background

Thymidylate synthase (TYMS) polymorphisms are reported to be related to susceptibility to some cancers. However, no study exists on TYMS polymorphisms and glioma risk. This study aimed to evaluate the relationship between two common TYMS gene variants (rs1059394 C>T, rs2847153 G>A) and glioma susceptibility.

Methods

This case-control study included 605 patients and 1300 cancer-free individuals. Genotyping was performed using Sequenom Mass-ARRAY. We determined odds ratios (ORs) and their 95% confidence intervals (CIs) to estimate the correlations.

Results

The analysis revealed that rs1059394 TT and CT+TT genotype had significantly low glioma risk (TT to CC: OR = 0.71, 95% CI = 0.52–0.97, P = 0.03; CT+TT to CC: OR = 0.74, 95% CI = 0.55–0.99, P = 0.04). However, no significant difference was found between rs2847153 and glioma risk in any genetic model (P﹥0.05). In high-grade gliomas, the GA and GA+AA genotypes of rs2847153 made the majority of genotypes, compared with GG genotype (GA to GG: OR = 2.01, 95% CI = 1.39–2.91, P < 0.001; GA+AA to GG: OR = 1.78, 95% CI =1.25–2.54, P < 0.001). Moreover, online expression quantitative trait locus (eQTL) analysis indicated that these two polymorphisms may alter TYMS gene expression in transformed fibroblast cells.

Conclusion

Our study provides evidence of the effect of TYMS rs1059394 on the susceptibility of glioma. In high-grade gliomas, compared with GG genotype, the GA and GA+AA genotypes of rs2847153 comprise a larger proportion.

Thymidylate synthase gene polymorphisms as important contributors affecting hepatocellular carcinoma prognosis

BACKGROUND

Thymidylate synthase (TYMS), a key rate-limiting enzyme in the folate metabolism, plays essential roles in the development of several malignancies including hepatocellular carcinoma (HCC). Nonetheless, the association of the single nucleotide polymorphisms (SNPs) in TYMS gene with the prognosis of Chinese HCC patients remains unknown.

METHODS

A total of 492 HCC patients who underwent surgery treatment were included in this study. Five functional SNPs (rs2847153, rs2853533, rs502396, rs523230, and rs9967368) in TYMS gene were genotyped using the iPLEX genotyping system. Multivariate Cox proportional hazards regression model and Kaplan-Meier curve were used to analyze the association of SNPs with survival and recurrence of HCC patients.

RESULTS

Two SNPs (rs523230 and rs9967368) in TYMS gene were significantly associated with the overall survival of HCC patients. Patients carrying homozygous variant genotype (VV) of rs523230 had significantly decreased risk of death (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.46-1.00; P=0.048) when compared with those carrying homozygous wild-type (WW) or heterozygous (WV) genotypes, while patients carrying WV+VV genotype of rs9967368 had significantly increased risk of death (HR, 1.46; 95% CI, 1.05-2.04; P=0.026) when compared with those carrying WW genotypes. Cumulative effect analysis showed a significant dose-dependent effect of unfavorable SNPs on OS.

CONCLUSIONS

Our study for the first time demonstrates the association of SNPs in TYMS gene and clinical outcome of HCC, suggesting that rs523230 and rs9967368 in TYMS gene might be used to predict clinical outcome of Chinese HCC patients.