Myung and Yan confirmed the tumor suppressor activity of 15-PGDH through the restoration of 15-PGDH expression in human colon cancer cells, which blocks the ability of these cells to form tumors in nude mice hosts, and showed that knocking out the murine 15-PGDH gene markedly sensitizes mice to colon tumor development [16, 18]. The gene discussed is HPGD; the disease is neoplasm.