ABSTRACT
<p><b>BACKGROUND</b>Methylenetetrahydrofolate reductase (MTHFR) plays an important role in metabolism of folate and DNA methylation. In vitro, many studies have demonstrated that abnormal methylation of some genes may affect the sensitivity of tumor cells to cytotoxic drugs and agents interfering with DNA synthesis. The aim of this study is to investigate the relationship between genetic polymorphisms of MTHFR C677T or A1298C and the response to platinum-based chemotherapy in non-small cell lung cancer (NSCLC).</p><p><b>METHODS</b>A total of 97 patients with NSCLC were analyzed. MTHFR genotypes were detected in all the patients by PCR-RFLP method. All the patients were treated with platinum-based chemotherapy.</p><p><b>RESULTS</b>(1) Out of all the cases, the frequencies of MTHFR C677T C/C, C/T and T/T genotypes were 34.0%, 50.5% and 15.5%, respectively, while the frequencies of MTHFR A1298C A/A, A/C and C/C genotypes were 64.6%, 29.2% and 6.3%, respectively. The overall response rate (complete and partial response) to platinum-based chemotherapy was 39.2%. (2) No significant difference in response rate to chemotherapy was observed according to the MTHFR C677T or A1298C genotypes. However, MTHFR C677T and A1298C polymorphisms showed a synergic effect on chemotherapeutic efficacy, the response rate of patients with MTHFR C677T T allele and A1298C A/A genotype (51.1%) was significantly higher than those with MTHFR C677T C/T and A1298C C allele (12.5%)(P=0.007, OR=7.30, 95% CI: 1.34-52.47).</p><p><b>CONCLUSIONS</b>The results suggest that the synergic effect between MTHFR C677T and A1298C polymorphisms is associated with clinical response to platinum-based chemotherapy. Detection of MTHFR genotypes may indicate the sensitivity of NSCLC patients to platinum-based chemotherapy.</p>
ABSTRACT
<p><b>OBJECTIVE</b>In order to study the relation between polymorphisms of methylenetetrahydrofolate reductase C677T (MTHFR) and susceptibility of stomach cancer (SC).</p><p><b>METHODS</b>We conducted a case-control study with 107 cases of SC and 200 population-based controls in Huaian city of Jiangsu province, China. The epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects. MTHFR genotypes were detected by PCR-RFLP method.</p><p><b>RESULTS</b>(1) The frequency of MTHFR variant genotypes (C/T + T/T) among the cases (79.4%) was significantly higher than the controls (68.5%) (P = 0.041 6); the crude OR for SC was 1.78 (95% CI: 0.99 - 3.22). After adjustment for sex and age, the OR for SC was 1.89 (95% CI: 1.08 - 3.32). (2) Subjects who had MTHFR variant genotypes and having smoking habit were at a significantly higher risk of developing SC (OR = 7.72, 95% CI: 2.23 - 26.79) compared with those who had wild-type homozygotes (C/C) genotype and no smoking habit. Individuals who had variant genotypes and who had habit of frequent alcohol drinking were at an increased risk of developing SC (OR = 3.08, 95% CI: 1.30 - 7.23) compared with those with C/C genotype and low consumption of alcohol. As compared with subjects with C/C genotype and low consumption of alcohol and no smoking habit, individuals who had variant genotypes and who had habits of frequent alcohol drinking and smoking had 12.96 (95% CI: 2.76 - 70.46) folds risk developing SC.</p><p><b>CONCLUSIONS</b>These results in the present study suggested that the polymorphisms of MTHFR C677T was associated with risk of developing SC, and there was a coordinated effect between MTHFR genotypes and habits of smoking and alcohol drinking in the development of SC.</p>