[Clinical significance of ID4 methylation detection by quantitative methylation-specific PCR in acute leukemia]

The advances of treatment improved the prognosis of the patients with acute leukemia (AL) in the last decade, but the lack of general biomarker for predicting relapse in AL, which is one of the most important factors influencing the survival and prognosis. DNA methylation of ID4 gene promoter occurred frequently in patients with AL and was found to be highly related to the tumor progression. Based on the previous work of the setup of methylation-specific quantitative PCR system for ID4 gene, this study was designed to investigate the relation between the quantitative indicator of methylation density, percentage of methylation reference(PMR) value, and different disease status of AL. PMR of ID4 was detected by MS-PCR in bone marrow (BM) samples of 17 healthy persons and 54 AL patients in the status of newly diagnosis, complete remission and disease relapse. The results showed that at different disease status, PMR value in newly diagnosed group was significantly lower than that in complete remission group (P = 0.031). Among serial samples, PMR value remained very low at the status of patients with continuous complete remission (<1.5‰), and increased along with the accumulation of tumor cells at relapse. In 1 relapse case, the abnormal rise of PMR value occurred prior to morphological relapse. PMR value seemed to be related to body tumor cell load. It is concluded that the quantitative indicator of methylation density and PMR value may reflect the change of tumor cell load in acute leukemia patients. Dynamic monitoring of PMR maybe predict leukemia relapse.