More than 98% of acute promyelocytic leukemia (APL) patients have classic t(15,17)(q22;q12-23) and promyelocytic leukemia-retinoic acid receptorА (PML-RARА) fusion genes; they respond to all-trans retinoic acid (ATRA) and have a good prognosis. The gene discussed is PML; the disease is acute promyelocytic leukemia.