In blast crisis, increased expression of the BCR/ABL oncoprotein accounts for the block of differentiation, inactivation of factors with tumour suppressor activity and decreased genomic stability of the Ph1 blasts (Perrotti et al, 2002; Skorski, 2002; Trotta et al, 2003; Calabretta and Perrotti, 2004; Neviani et al, 2005). This evidence concerns the gene BCR and neoplasm.