Among haematopoietic tumours, aberrant methylation of promoter-associated CpG islands (CGIs) in oestrogen receptor, p16INK4A, p15INK4B, p73, p57KIP2 and DAP kinase has been observed in acute lymphocytic leukaemia (ALL), acute myeloid leukaemia (AML), malignant lymphoma and multiple myeloma (Herman et al, 1997; Katzenellenbogen et al, 1999; Garcia-Manero et al, 2002a, 2002b; Li et al, 2002). This evidence concerns the gene CDKN2A and acute lymphoblastic leukemia.