Incidence of the 15q+;17q- chromosome translocation in acute promyelocytic leukaemia (APL).

Cytogenetic analysis was carried out on peripheral blood cultures from seven patients with acute promyelocytic leukaemia (APL-M3). A reciprocal 15;17 chromosome translocation, t(15q+;17q-), was found in all cases, and the breakpoints estimated to be 15q22 and 17q12-21. In addition to the t(15q+;17q-), trisomy 10 was found in 50% of cells analysed in one case. These results suggest that the 15;17 chromosome translocation may be observed in most cases of APL where the leukaemic cells are cultured before cytogenetic analysis is performed. The use of conditioned media in the culture of leukaemic cells is also described.