SNPs in MTRR (rs13162612; OR = 0.25; 95% CI: 0.11-0.58; rs10512948; OR = 0.61; 95% CI: 0.41-0.90; rs2924471; OR = 3.31; 95% CI: 1.66-6.59), and MTHFR (rs9651118; OR = 0.63; 95% CI: 0.43-0.95) and three SNP*nutrient interactions (choline*rs10475407; OR = 1.62; 95% CI: 1.11-2.42; choline*rs11134290; OR = 0.51; 95% CI: 0.27-0.92; and riboflavin*rs8767412; OR = 0.40; 95% CI: 0.15-0.95) were associated with lung cancer risk in never smokers.
To investigate whether such polymorphisms influence lung cancer survival, we genotyped 14 nsSNPs mapping to methylene-tetrahydrofolate reductase (MTHFR), methionine synthase (MTR), methionine synthase reductase (MTRR); DNA methyltransferase (DNMT2), methylenetetrahydrofolate dehydrogenase (MTHFD1) and methenyltetrahydrofolate synthetase (MTHFS) in 619 Caucasian women with incident disease, 465 with non-small cell (NSCLC) and 154 with small cell lung cancer (SCLC).
In addition, we found interactions between the MTRRA66G polymorphism and smoking (P = 0.015) and the MTHFR A1,298C polymorphism and alcohol consumption (P = 0.025) for risk of lung cancer overall.
In conclusion, our data provide evidence supporting the association between the MTR 2756A>G and MTRR 66A>G polymorphisms and lung cancer risk, which may be modulated by dietary nutrient intake.