In tumor cells, the enhanced expression of serine hydroxymethyltransferase 2 (SHMT2) leads to the excessive catalysis of serine into glycine [103], which participates in the tetrahydrofolic acid reaction, promotes the metabolism of one carbon unit, and synthesizes the nucleotides, lipids, and proteins required for cell proliferation [104]. This evidence concerns the gene SHMT2 and neoplasm.