Unrelated clonal chromosome abnormalities in myelodysplastic syndromes and acute myeloid leukemias.

Most neoplasms are monoclonal and the tumor cells are believed to be the progeny of a single transformed cell. Clonality has been demonstrated by X-chromosomal enzymes, immunoglobulin and T-cell receptor gene rearrangements, or clonal cytogenetic abnormalities. Nevertheless, cytogenetically unrelated clones with disparate chromosome abnormalities are found infrequently in hematologic malignancies. We report four kinds of coexisting independent clones, +8/+21, der(1;7)/+8, del(9)/-X/i(Xq), and i(7p)/+11, respectively, which to our knowledge mostly have not been reported in same individuals, in two myelodysplastic syndrome and two acute myeloid leukemia cases.