In our present comparison we would have expected that, for example, BCR/ABL-positive leukaemias, i.e. the clinical material and the respective cell line, would primarily be allocated to a common gene expression profile group, and clearly be separated from BCR/ABL-negative leukaemias, given the strong impact of the BCR/ABL fusion gene in the molecular pathology of CML. Here, BCR is linked to leukemia.