MTHFR and non-small cell lung carcinoma: Our results show that analysis of VNTR polymorphism in TS gene, an inside G > C SNP in VNTRs and MTHFR gene 677C > T SNP might help in selecting a group of non-squamous NSCLC patients who will benefit significantly from pemetrexed monotherapy, but in order to evaluate properly the usefulness of the chosen molecular factors more large-scale and prospective studies on more representative groups are needed.