[A preliminary study on the implication of Apaf-1 promoter methylation and the expression of apoptosis inhibitor protein Apollon in adult acute leukemia].

OBJECTIVE: To investigate the role of Apaf-1 gene promoter methylation and apoptosis inhibitor protein Apollon in pathogenesis of acute leukemia (AL) and their clinical significance. METHODS: Methylation specific PCR (MSP) was used to detect the methylation status of Apaf-1 gene promoter in 53 AL patients (28 AML, 10 ALL and 15 relapsed) and 10 healthy or nonmalignant blood diseases patients as control. RT-PCR was used to detect the expression levels of Apaf-1 mRNA and immunocytochemistry to detect the expression levels of Apollon protein. RESULTS: The abnromal methylation of Apaf-1 gene promotor in AL was 18/53(33.9%). No Apaf-1 mRNA was detected in methylation positive patients. Only one case in healthy and nonmalignant individuals was deletion of Apaf-1 mRNA expression without abnormal methylation. The positive methylation rate in AL bone marrow mononuclear cells was significantly higher than that in controls (P < 0.05). The expressin levels of Apollon protein in AL patients was higher than that in control (P < 0.05). The positive methylation ratio and Apollon protein level were higher in white blood cell count > 10 × 10(9)/L than in ≤ 10 × 10(9)/L (P < 0.05). There is a positive correlaiton between positive methylation ratio and Apollon protein expression in AL patients. CONCLUSION: Abnormal methylation of Apaf-1 gene promotor and high expression of Apollon might involved in leukemogenesis.