Translocation (3;21)(q26;q22) in treatment-related acute leukemia secondary to acute promyelocytic leukemia.

We performed cytogenetic studies in a patient with treatment-related acute leukemia (t-AL) to identify the associated chromosomal changes. Metaphase analysis revealed a t(3;21)(q26;q22) translocation. Acute promyelocytic leukemia (APL) had been diagnosed 4 years earlier and the patient had received intensive induction chemotherapy and sequential post-induction therapy that included agents that targeted DNA-topoisomerase II (topo II). This case suggests an association between previous therapy with topo II inhibitors and development of t-AL associated with a balanced aberration involving the 3q26 and 21q22 bands.