Through the identification of new tumor suppressor genes by analysis of non-random deletions in this region,13 and through the analysis of the p15, p16 and p19 genes located in this region, the role of their inactivation in the genesis and evolution of lymphohematopoietic neoplasias, especially childhood acute lymphoblastic leukemia, has been studied. Here, CDKN2A is linked to acute lymphoblastic leukemia.