TP53 and acute lymphoblastic leukemia: Our current results not only further increase the number of genes described as aberrantly methylated in ALL but more importantly indicate that one of the pathways most frequently deregulated in different cancers such as TP53 is altered in ALL not due to genetic events but rather to the abnormal hypermethylation of many genes involved in p53 induced apopotosis, cell cycle and p53 regulation.