白血病患者p16基因失活机制研究

Study on the deletion point mutation and promoter methylation analysis of p16 in leukemia

目的了解白血病患者p16基因纯合性缺失、点突变及启动子区甲基化状态,探讨白血病发生中p16基因失活机制。方法采用聚合酶链反应、聚合酶链反应-单链构象多态性以及巢式甲基化特异性PCR法,对57例白血病患者进行p16基因纯合性缺失、点突变及启动子区甲基化状态研究。结果在受检的57例白血病患者中,共有6例发生p16基因纯合性缺失(10.53%);无p16第1、2外显子缺失的51例白血病患者中均未见点突变发生;无p16基因第1、2外显子缺失、突变的51例白血病患者中共有16例发生p16基因甲基化(31.37%),其中14例(27.45%)发生在急性白血病患者;57例白血病患者中共有22例发生p16基因失活(38.60%)。结论白血病发生过程中表观遗传学机制和遗传学机制相互作用,p16基因启动子区高甲基化可能是急性白血病发生中p16基因失活的主要机制。

Objective To investigate the deletion,the point mutation and the hypermethylation of promoter of p16 in leukemia and to discuss the mechanism of p16 gene inactivation in leukemia.Methods The deletion,point mutation and hypermethylation status of the promoter-associated CpG islands of p16 were analyzed by polymerase Chain Reaction （PCR）,PCR-single strand conformation polymorphism（PCR-SSCP） and nested methylation-specific PCR（nMSP） in 57 cases leukemia （AML） at diagnosis.Results Among 57 patients,only 6 cases deletions of p16（10.5%） were found.The mutation was not observed in any case.Methylation analysis of p16 gene promoter revealed hypermethylation of CpG islands in 16/51 cases （31.37%）.Hypermethylation of p16 was observed in 27.45% of acute leukemia.Among 57 patients,the p16 gene inactivation were observed in 22 cases（38.60%）.Conclusion Both epigenetic and genetic alternations were involved in leukemia formation.The genetic alterations including the deletion and the mutation of p16 gene were rare events whereas hypermethylation of p16 was the common event in acute leukemia.