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

Abstract

Summary Cytogenetic analysis was carried out on peripheral blood cultures from seven patients with acute promyelocytic leukaemia . A reciprocal 15;17 chromosome translocation, t(lSq +; 17q -), was found in all cases, and the breakpoints estimated to be 15q22 and 17ql2-21. 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.

Genetic damage and escape from proliferation control

“…Almost all cases of acute promyelocytic leukaemia (APL, FAB M3 and M3 variants) are characterized by a translocation between chromosomes 15 and 17,1(15;17)(q22;q12-21), found in the malignant promyelocytes (Sheer et al, 1985;Larson et al, 1984). The disease represents a failure of these promyelocytes to differentiate and results in the accumulation of immature myeloid cells in the bone marrow, blood and visceral organs.…”

Molecular analysis of the t(15;17) translocation in acute promyelocytic leukaemia

“…The incidence of the t(15;17) translocation in APL equals the association of the t(9;22) with CML, and it has been suggested that the t(15;17) may be found in every case of APL if optimal analysis is performed (Larson et al, 1984;Sheer et al, 1985). This requires the culture of the bone marrow for 24-48 hours prior to banding to permit the translocation-bearing malignant cells to outgrow the cytogenetically normal erythroblasts (Berger et aly 1983).…”

“…Cytogenetic analysis of patients with APL has established that the majority of patients present with a typical t(15;17) translocation (Larson et alt 1984;Sheer et al, 1985). Patients who fail to demonstrate the standard t(15;17) translocation are rare, and are divided into three classes: A) those with complex translocations; B) those with simple variant translocations and C) those that entirely lack the t(15; 17) or any of its variants.…”