Chromosome abnormalities in human acute nonlymphocytic leukemia: relationship to age, sex, and exposure to mutagens.

Nonrandom chromosome changes have been observed in human acute nonlymphocytic leukemia (ANLL). Two specific translocations have been detected only in ANLL arrested in a particular stage in myeloid maturation, i.e., t(8;21) associated with acute myeloblastic leukemia (AML) with maturation (M2) and t(15;17) associated with acute promyelocytic leukemia (M3). Patients with these translocations are substantially younger then patients with the same type of leukemia who have either a normal karyotype or other chromosome abnormalities. Patients who have ANLL secondary to treatment for a prior malignant disease tend to have AML (M1 or M2) and an abnormal karyotype with losses of chromosome #5 and/or #7. A similar high incidence of AML and aneuploidy affecting particularly #5, 7, 8, and 21 was seen in patients with ANLL who were exposed to chemicals and pesticides. Complete unselected data are available for 239 patients with ANLL; 128 of these were classified as having AML (M1 or M2). Within the AML group, 65% of the patients were chromosomally abnormal. Except for 16 patients with a t(8;21), the percentage of those with an abnormal karyotype increased with age, particularly above the age of 50 years. In regard to abnormalities other than t(8;21), 29 patients had loss of part of all of #5 and/or #7, 11 had +8, and 27 had other abnormalities. On the other hand, of 70 patients with acute myelomonocytic leukemia (M4), 42 were normal, only 3 had loss of #5 or 7, 1 was -7, +8, and 4 were +8, whereas 20 had other abnormalities. This difference in karyotype may reflect different etiologic factors in these two types of leukemia.