MTHFR and non-small cell lung carcinoma: The functional polymorphisms in genes TP53 (rs1042522), MDM2 (rs2279744), MDM4 (rs4245739), MTHFR (rs1801133), CASP8 (rs3834129), and CCR5 (rs333) alone or in combination, could affect survival in advanced non-small cell lung cancer (NSCLC) patients [13] (Figure 1).