Further cytogenetic studies on acute promyelocytic leukemia

Chromosomes were analyzed in nine cases of acute promyelocytic leukemia (APL-M3), including a follow-up case and an erroneously diagnosed case from our previous reports. The reciprocal 15;17 translocation, t(15q+; 17q-), was found in all cases, and the break points were estimated to be 15q22 or q23 and 17q12. In addition, trisomy 8 and an isochromosome of the long arm of the affected chromosome #17, i(17q-), were observed in two cases each. Some other abnormalities were encountered, mostly in remission or relapse. The disappearance and repopulation of t(15q+; 17q-) cells were associated with complete remission and relapse, respectively, in two repeatedly analyzed cases. Including the previously reported cases, we investigated a total of 12 cases of APL, and all were found to be associated with t(15q; 17q-). The mean age of the 12 patients was 34.25 +/- 3.12 [SD] years, and their mean survival 266.3 +/- 95.97 [SD] days.