Thymidylate Synthase Polymorphisms and Risk of Lung Cancer among the Jordanian Population: a Case Control Study

Association of MTHFR and TYMS gene polymorphisms with the susceptibility to HCC in Egyptian HCV cirrhotic patients

Identification of host genetic factors influencing the risk of developing hepatocellular carcinoma (HCC) in patients with chronic hepatitis C virus (HCV) infection may help to refine patients' selection to benefit from specific preventative measures and/or adapted screening policies. Thus, this study aimed to investigate the association of MTHFR c.677C > T and c.1298A > C in addition to TYMS 3'-UTR 6-bp ins/del polymorphisms with the susceptibility to HCV-related HCC in an Egyptian population. Polymerase chain reaction-restriction fragment length polymorphism was performed to genotype the polymorphisms in 194 HCV-infected patients subdivided into liver cirrhotic (LC, n = 104) and HCC (n = 90) patients as well as 100 healthy subjects. In healthy controls, the MTHFR c.677C > T polymorphism under the homozygous and recessive models (p = 0.005) and the c.1298A > C polymorphism under all the tested genetic models (p-values range from < 0.001 to 0.007) were associated with an increased risk of HCC. In LC patients, the MTHFR c.677C > T polymorphism under the homozygous, dominant, and recessive models (p-values range from 0.001 to 0.007), as well as MTHFR c.1298A > C under the homozygous model only (p = 0.014), increased the susceptibility to HCC. The C/C and T/C haplotypes of MTHFR c.677C > T and MTHFR c.1298A > C polymorphisms were contributed to an increased risk of healthy subjects to develop HCC (p-values range from < 0.001 to 0.015), while only the T/C haplotype was associated with the progression of HCC in LC patients (p = 0.001). In conclusion, MTHFR c.677C > T and c.1298A > C in addition to their haplotypes may contribute to the development of HCV-related HCC in an Egyptian population. These findings may aid in the early diagnosis and management of HCC.

Association between polymorphisms of thymidylate synthase gene 5'- and 3'-UTR and gastric cancer risk: meta-analysis

Gastric cancer is the most common cancer and the most frequent cause of cancer death worldwide. Several studies have identified the role of thymidylate synthase (TS) 5′- and 3′-UTR and gastric cancer susceptibility; however, the results still remain inconclusive. The purpose of this meta-analysis was to reinvestigate this correlation. In the present study, online databases were searched to retrieve relevant articles published between January 2000 and 2016. The odds ratio (OR) and 95% confidence interval (CI) were employed to calculate the strength of association. Overall, a total of 13 articles were screened out, including 2382 gastric cancer patients and 3171 healthy controls. We found that polymorphisms of TS 5′-UTR 2R (double repeats)/3R (triple repeats) of a 28-bp sequence (11 articles) and 3′-UTR del6/ins6 (seven articles) were not significantly associated with increased risk of gastric cancer. Subgroup analysis by ethnicity showed that 2R allele and 2R/2R genotype in TS 5′-UTR were associated with gastric cancer susceptibility in Caucasian and African populations; del6 allele, del6/del6 and del6/ins6 genotypes were correlated with gastric cancer in Caucasian population. In conclusion, our result suggested that TS polymorphisms might be the risk factors for gastric cancer risk in Caucasian population, although this association needs further study, and future large-scale researches are still required.