MTHFD1 and squamous cell carcinoma: In the TCGA datasets of the two main subtypes of NSCLC, adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC), PSAT1, SHMT1, SHMT2, MTHFD1 and MTHFD2 were significantly overexpressed compared to normal lung tissue (Fig. 1B).