Emergence of karyotypically unrelated clone in remission of de novo acute myeloblastic leukaemias.

Serial cytogenetic analysis revealed karyotypically unrelated clones in four patients with acute myeloblastic leukaemia (AML) in remission. At diagnosis, three patients had t(8;21)(q22;q22) and one had an inv(16)(p13q22). After 18-22 months in remission, different clones emerged in each patient with myelodysplastic features of the bone marrow cells. The emergence of clones with abnormalities of chromosome 7 in remission seems to be an unfavourable factor for prognosis.