All these studies combined suggest that the expression of ETV6-RUNX1 leads to an arrest in the B cell differentiation, but the complete arrest and proliferation of leukaemia blasts requires additional genetic events such as the loss of Pax5 or Cdkn2a activity, which are potentially mediated by an elevated RAG-mediated recombination. This evidence concerns the gene CDKN2A and leukemia.