Our analysis of methylation status of APAF-1 gene promoter in patients with AML showed that APAF-1 hypermethylation frequency was 56.4% (57/101).Methylation of the Apaf-1 gene promoter has been demonstrated in AML, CML, and ALL, suggesting that methylation contributes to the inactivation of Apaf-1 expression   16 . The gene discussed is APAF1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.