Relationship between Glutathione S-Transferase P1 (GSTP1), X-Ray Repair Cross Complementing Group 1 (XRCC1) and 5,10-Methylenetetrahydrofolate Reductase (5,10-MTHFR) Gene Polymorphisms and Response to Chemotherapy in Advanced Gastric Cancer

Background: Our study aimed to investigate the relationship between glutathione S-transferase P1 (GSTP1), 5,10-methylenetetrahydrofolate reductase (5,10-MTHFR) and X-ray repair cross complementing group 1 (XRCC1) gene polymorphisms and the response to chemotherapy in advanced gastric cancer. Patients and Methods: 59 cases of advanced gastric cancer were enrolled. All patients were treated with the DCF regimen comprising docetaxel, cisplatin, and 5-fluorouracil. All patients' genotypes regarding GSTP1, XRCC1, and 5,10-MTHFR were analyzed by polymerase chain reaction/ligase detection reaction (PCR-LDR). Results: There were 15 (25.42%) cases of G/G genotype, 21 (35.59%) of G/A genotype, and 23 (38.98%) of A/A genotype for GSTP1, 16 (27.12%) cases of A/A genotype, 18 (30.51%) of G/A genotype, and 25 (42.37%) of G/G genotype for XRCC1, and 21 (35.59%) cases of C/C genotype, 22 (37.29%) of C/T genotype, and 16 (27.12%) of T/T genotype for 5,10-MTHFR. After 2 cycles of chemotherapy, there were 4 cases of complete remission, 14 of partial remission, 19 of stable disease, and 22 of advanced disease, with a total effective rate of 30.51%. Better survival was shown for GSTP1 G/G genotype, XRCC1 A/A genotype, and 5,10-MTHFR T/T genotype (p < 0.05). Conclusion: The gene polymorphisms of GSTP1 G/G, XRCC1 A/A, and 5,10-MTHFR T/T have clinical value for predicting the response to the DCF regimen for advanced gastric cancer.