Aberrant p15 gene promoter methylation in therapy‐related myelodysplastic syndrome and acute myeloid leukaemia: clinicopathological and karyotypic associations

Seventeen patients with therapy‐related myelodysplastic syndrome/acute myeloid leukaemia (t‐MDS/AML) were examined for aberrant p15 gene methylation by methylation‐specific polymerase chain reaction. Ten patients (58%) showed p15 methylation, which was significantly related to monosomy/deletion of chromosome 7q, but not to antecedent chemotherapy, blast count, leukaemic evolution or survival. In three of six patients with marrow samples obtained prior to the diagnosis of t‐MDS/AML, p15 methylation predated disease development by up to 2 years. Bone marrow transplantation led to the disappearance of p15 methylation in one patient. These results showed that p15 methylation was an early event in the evolution of some t‐MDS/AML patients.