MTR and lung carcinoma: As in the previous studies, we found no association between the MTR c.2756A>G [14–16, 18], MTRR c.66A [14, 19], SHMT1 c.1420C>T [14, 24] and TYMS: 5’UTR 2R/3R [15] polymorphisms and lung cancer risk in a general population.