Upregulation of 15-PGDH gene expression through activation of activating protein-1 (AP-1) is one of the mechanisms reported for the antitumor properties of 15d-PGJ2 in human colon cancer cell line HCT-116 (Park and Na, 2019a; Park and Na, 2019b). The gene discussed is HPGD; the disease is malignant colon neoplasm.