Another cancer treatment success story involves the repurposing of all-trans retinoic acid (ATRA), a chemical compound historically used in medications that treat severe acne. Though it does not have anti-cancer properties when used alone, ATRA has been combined with traditional chemotherapy and to induce complete remission in 90% of patients with acute promyelocytic leukemia. The drug combination has also been proven to significantly decrease the chance of relapse among leukemia patients in remission (1).

1. Fenaux P., Chomienne C., and Degos L (2001). All-trans retinoid acid and chemotherapy in the treatment of acute promyelocytic leukemia. Seminars in Hematology 38(1): 13-25. [Link here]