淋巴细胞恶性肿瘤p16基因纯合缺失和突变的研究

Study on homozygous deletion, mutation of p16 gene in malignant lymphoma

为了探讨非霍奇金淋巴瘤(NHL)和急性淋巴细胞白血病(ALL)中p16基因纯合缺失和突变情况,应用聚合酶链反应(PCR)技术与DNA单链构象多态性分析(PCR-SSCP)及DNA测序技术,检测了45例NHL及20例ALL p16基因改变情况。结果发现45例NHL中有4例存在p16基因纯合缺失,占8.9％,20例ALL中有5例存在p16基因纯合缺失,占25％。1例NHL在第2外显子上游第49密码子出现错义突变,由GCC突变为GAC。1例ALL在第2外显子上游65密码子出现错义突变,由GCC改变为GCA。研究结果表明,NHL和ALL中存在一定比例的p16基因纯合缺失,而p16基因突变率较低,提示p16基因纯合缺失在NHL和ALL发生发展中起一定作用。

To investigate the homozygous deletions and mutations of p16 gene in the genesis and development of non-Hodgkin's lymphoma (NHL) and acute lymphoblastic leukemia (ALL), paraffin-embedded biopsies from 45 patients with NHL and bone marrow mononuclear cells from 20 patients with ALL were examined by using poly-merase chain reaction (PCR), PCR amplification in conjunction with single-strand conformation polymorphism (PCR-SSCP) analysis as well as direct PCR product sequencing techniques. Results showed that homozygous deletions were detected in 4 of the 45 cases of NHL (8.9%) and in 5 of the 20 cases of ALL (25 % ), while mutations at exon 2 of p16 were found in two of all malignant lymphoma cases, with one showing the GCC to GAC missense mutation (Ala to Asp) at codon 49 in NHL, and the other showing a GCC to GCA missense mutation (Ala to Arg) at codon 65 in ALL. There was certain proportion of homozygous deletions of p16 gene in NHL and ALL, which indicated that p16 gene inactivation may play an important role in the genesis and development of NHL and ALL, and the homozygous deletions may be one of the mechanism of the p16 gene inactivation. The inactivation of p16 gene by point mutation was an uncommon event either in ALL or in NHL.