No significant association between the MTHFR c.665C>T polymorphism and lung cancer risk was found, although a trend towards lower risk of lung cancer among T allele carriers as compared to the CC genotype was observed (OR = 0.68, 95% CI: 0.45–1.01, P = 0.057, Table 3). The gene discussed is MTHFR; the disease is lung carcinoma.