ABL amplification in a patient with lymphoid blast crisis of chronic myelogenous leukaemia

Although chronic phase myelogenous leukaemia (CML) is characterised by the Philadelphia (Ph) chromosome leading to a fusion of the BCR and ABL genes, additional genetic alterations involved in blast crisis are poorly understo od. We report an at least 15-fold amplification of the ABL oncogene in a 29 -year-old male patient with a variant Ph-positive t(19;22)(p13;q11.2) CML w ho presented in lymphoid blast crisis. Our finding suggests that an amplifi cation of the ABL oncogene might play a part in the appearance of an aggres sive phenotype in some cases of CML.