Cytogenetic characteristics of therapy‐related acute nonlymphocytic leukaemia, preleukaemia and acute myeloproliferative syndrome: correlation with clinical data for 61 consecutive cases

Summary Cytogenetic studies were performed on a new series of 23 patients with therapy‐related acute non‐lymphocytic leukaemia, preleukaemia or an acute myeloproliferative syndrome. In our total series of now 61 cases studied by chromosome banding techniques, at least one of the abnormalities – 7, 5q –, 7q– or – 5 or some related unbalanced translocations, primarily – 7, +t(1q7p), was observed in 40 patients. The critical region for the deletions of chromosome no. 5 comprises bands 5q22 to 5q33 and of chromosome no. 7 bands distal to 7q22. The third most frequently involved chromosome was no. 21, rearranged at band 21q22 in the three patients with 21q + and in one patient with 21q –. An i(21q) was observed in two patients, a –21 in four patients and a –22, + t(21q22q) and a –5.–21, + t(5p21q) in one patient each. Other characteristic abnormalities included total loss or rearrangements of the short arm of chromosome no. 17, observed in nine patients. One patient had a –12, three others had rearrangements resulting in a partial or total loss of the short arm of chromosome no. 12. A 19q + with translocation to band 19q13 was observed in three cases, a – 18 in three cases and a 3p– in four cases. Thirty‐one patients with multiple chromosome aberrations experienced a significantly shorter survival as compared to 13 patients with a normal karyotype ( P = 0·02) and 17 patients with one single chromosome aberration ( P <0·01).