SHMT2 and esophageal cancer: Serine hydroxymethyl transferase 2 (SHMT2) is involved in esophageal cancer progression by interacting with Methylenetetrahy-drofolate Dehydrogenase 1 Like (MTHFD1L), while hypoxia-induced SHMT2 Kla in turn enhanced MTHFD1L expression and accelerated the malignant progression of EC cells [68].