Abstract
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).