Acute promyelocytic leukemia: cytogenetics and bone-marrow culture.

Six patients were diagnosed as having acute promyelocytic leukemia (APL) according to FAB criteria. One patient conformed to the M3 variant. Informative cytogenetic results (G-banding) on five of the patients showed that three of them, including the M3 variant, had the 15;17 translocation in bone-marrow or blood cells. Cells with the translocation were accompanied by cells with a normal karyotype in all patients and no other chromosomal abnormality was present. This first report of the 15;17 translocation from the South Pacific region is relevant to the uneven geographical distribution of APL patients with the translocation. Five of the six patients including the M3 variant, showed a distinctive pattern of cell growth in agar culture characterized by a profusion of small, uniform clusters containing 6-20 cells with the appearance of promyelocytes. The remaining patient had a pattern of cell growth more typical of M2 acute leukemia. This cell growth pattern may be useful in diagnosing and monitoring the course of APL.