165例恶性淋巴瘤中p16基因异常的研究

目的 检测恶性淋巴瘤（ML）中p16基因的缺失、甲基化及p16蛋白的表达，探讨p16基因异常在淋巴瘤中的意义。方法 收集淋巴瘤鹇组织标本50例，存档石蜡包埋组织标本115例，均包括T、B非霍奇金淋巴瘤（NHL）及霍奇金淋巴瘤（HL）。用PCR、甲基化特异的PCR方法检测新鲜组织中的p16基因的等位缺失及5‘CgG岛异常甲基化；用免疫组织化学方法检测石蜡标本中p16蛋白的表达情况。另外，分别选取9例反应性增生（RH）组织的标本作对照。结果 12/50例（24.0%）新鲜标本中检出p16基因纯合性缺失，16/50例（32.0%）检出p16基因异常高甲基化；石蜡包埋标本中p16蛋白的失表达率为41.6%，其中B-NHL为46.0%，T-NHL为54.5%,HL为31.6%。恶性程度较高的淋巴瘤类型中p16蛋白的失表达率也相应较高，各类型之间比较：弥漫性大B细胞淋巴瘤（DLBCL）和滤泡性淋巴瘤（FL）的p16失表达率存在组间差异的显著性。所有RH标本均未见p16基因或蛋白表达的异常。结论 恶性淋巴瘤中p16基因的异常是一个频发事件，p16基因表达异常参与了淋巴瘤的发生及进展。

A Study of p16 Gene Abnormality in 165 Cases with Malignant Lymphoma

Purpose To investigate the frequencies of p16 gene deletion,methylation and the loss of p16 protein expression and to evaluate their clinicopathological implication in malignant lymphomas. Methods Fifty fresh and 115 paraffin fixed,formalin embedded lymphoma tissue samples were studied.PCR amplification was employed to detect homozygous deletion of p16 gene while restriction enzyme specific PCR technique was used to detect hypermethylation of p16 gene 5' CpG island.We also performed immunohistochemical procedure to identify the expression of p16 protein.And 8 cases of reactive lymphoid hyperplasia were studied as negative control. Results The frequencies of p16 gene homozygous deletion and p16 gene methylation were 24.0% and 32.0%,respectively.The rates of the loss of p16 gene expression were 46.0 %,54.5% and 31.6% in B?NHL,T?NHL,and HL,respectively.The frequent p16 gene inactivation was generally limited to those high grade lymphoma subtypes.And no p16 abnormilities were observed in all of 9 RH cases. Conclusions p16 abnormality is a frequent event in malignant lymphoma,the abnormal p16 gene expression is involved in the tumorigenesis and progression of lymphoma.