Abnormality of chromosome number 1 in 3 cases of acute transformation of chronic myeloid leukemia

: The authors report three cases of Ph1-positive chronic myelogenous leukemia (CML) with chromosome no 1 abnormalities. Such abnormalities have seldom been reported: three cases out of 42 in blast crisis and none of the 70 patients in the chronic phase in our series. In case no 1 a translocation: (t(1q;14q) was noted. In case no 2 the rearrangement was more complex: partial duplication of the long arm of chromosome no 1 and presence of a 21q+ corresponding to chromosome no 21 on which a part of the long arm of chromosome no 1 was transferred. In case no 3 a double translocation was noted between chromosomes no 1 and no 11, involving either the p or q arm. A review of the literature shows that abnormalities of chromosome no 1 are more frequent during the blast crisis that in the chronic phase of CML. Chromosome no 1 abnormalities are found in a number of myeloproliferative syndromes but even more frequently in solid tumors. The rearrangement sites are reviewed by the authors. Such rearrangements of chromosome no 1 may indicate an increased potential of malignancy.