Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) is a key enzyme involved in the m1C cycle, which plays a role in metabolic reprogramming, immune evasion, and disease progression in multiple cancers, including prostate cancer, lung adenocarcinoma, and ESCA [45–49]. Here, MTHFD2 is linked to lung adenocarcinoma.