Clinical significance of the expression of DNA methyltransferase genes (DNMT) in acute leukemia patients / 中国实验血液学杂志

ABSTRACT

To investigate the relationship between the expression of DNMT and clinical prognosis in adult patients with acute leukemia (AL), the mRNA expressions of DNMT, p15(INK4B), mdr1 were measured in 72 AL patients and 20 normal controls by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR); the ratio of p15 CpG land methylation was measured in 56 AL patients and 14 normal controls by methylation-specific PCR (MSP-PCR). The results showed that all three DNMT mRNA expressions in AL patients were significantly higher than that in normal controls (P < 0.01). When the internal control was changed into PCNA, a kind of cell proliferation marker gene, the difference still showed a statistic significance. All three DNMT genes were significantly expressed and positively correlated with AL patients, showing high synergistic expression, and there was a negative correlation between the levels of p15, mdr1 gene expression and DNMT. The complete remission (CR) rate in AL patients with the positive expression of all DNMT genes was significantly higher than that of AL patients with partially positive or negative expression (P < 0.01) of DNMT genes. In 56 AL patients, the P15I(NK4B) was completely methylated in 55.4% (31 of 56), partly methylated in 21.4% (12 of 56) and all 14 cases of normal controls were not methylated. It is concluded that DNMT genes are abnormally high expressed in adult AL patients, which lead to methylation-silence of tumor suppressor genes by CpG land hypermethylation, the AL patients with high expression of DNMT are more sensitive to chemotherapy, which may be a good prognostic factor for AL patients.