SKP2 and lung cancer: In lung cancer, MTHFD2 knockdown decreased the levels of several cell cycle genes, including cyclin-A2 (CCNA2), minichromosome maintenance complex component 7 (MCM7) and S-phase kinase-associated protein 2 (SKP2), in cell lines and tumor xenograft tissues, while the opposite was observed with MTHFD2 overexpression41.