Differentiation Therapy of Acute Promyelocytic Leukemia with Tretinoin (All-trans-Retinoic Acid)

ACUTE promyelocytic leukemia makes up approximately 15 percent of the adult acute nonlymphoblastic leukemias. 1 The disease is associated with a specific cytogenetic abnormality, the translocation of a portion of the long arm of chromosome 17 onto the long arm of chromosome 15 — t(15;17)(q22;ql2–21). 2 During the past year, the breakpoint region for the chromosome 17 translocation has been cloned, 3 and molecular studies have revealed DNA rearrangements that clustered in the region of the first intron for the nuclear retinoic acid receptor—alpha (RAR-α). 4 ' 5 This rearrangement resulted in the expression of abnormal messenger RNA (mRNA) transcripts for RAR-α. 6 7 8 These findings were of . . .