Apart from the genes with a high frequency of copy number amplification, such as MYC and MDM2, we identified some genes with copy number loss, such as CDKN2A and CDKN2B. CDKN2A/B deletions were independent prognostic markers for both adult and paediatric lymphoblastic leukaemia (40). This evidence concerns the gene CDKN2A and acute lymphoblastic leukemia.