Tetraploidy (92,XXYY) in an acute nonlymphocytic leukemia (M1) patient following autologous bone marrow transplantation.

Tetraploidy (4n = 92) without structural chromosome aberrations was found in bone marrow cells of a patient with acute nonlymphocytic leukemia, FAB classification M1, following autologous bone marrow transplantation. This finding, which remained undetected during the remission phases and appeared at relapses, progressed to a hypotetraploid modal number (74 chromosomes) at the terminal phase of the disease. Together with two previous observations in patients with acute lymphoblastic leukemia with L2 morphology and a null cell immunotype, this observation supports the hypothesis that tetraploid karyotypes may represent unusual and aspecific patterns of clonal evolution.