CYTOGENETIC EVOLUTION AND CLONAL PROLIFERATION IN ACUTE TRANSFORMATION OF CHRONIC GRANULOCYTIC LEUKAEMIA

Cytogenetic studies were performed in two cases of chronic granulocytic leukaemia which had undergone acute transformation. Chromosome preparations were made in the first case by a direct technique from bone marrow aspirate, and in the second case by a newly developed method of splenic cell culture. In each case, leukaemic cell lines possessing the Philadelphia chromosome (Ph1) together with additional karyotypic anomalies were demonstrable. In both cases many cells acquired a second Ph' and hyperdiploid cell lines arose by that means and by the acquisition of further additional chromosomes. From a detailed analysis of the complex karyotypic alterations present, the stepwise occurrence of successive cytogenetic changes could be deduced, and there was evidence of clonal proliferation of these new cell lines. Information relating to the cytogenetic evolution of individual neoplasms may be of general significance in studies of the natural history of cancer. It is suggested that chronic granulocytic leukaemia provides a particularly good opportunity for the correlation of cytogenetic changes with the progression of a neoplastic process. This work was supported by a grant from the Anti-Cancer Council of Victoria. © 1968, The British Empire Cancer Campaign for Research. All rights reserved.