摘要目的　探讨软组织平滑肌肉瘤（LMS）中p16基因INK4A的甲基化状态及其与p16表达的关系。方法　应用MSP法检测38例软组织平滑肌肉瘤，10例平滑肌瘤及5例正常平滑肌组织中p16基因INK4A的甲基化状态，用免疫组织化学SP方法检测p16蛋白表达情况。结果　38例LMS中9例发生异常甲基化，异常甲基化率为23.7%（9/38）。其中，7例p16蛋白表达阴性，2例p16蛋白弱阳性。在p16蛋白表达阴性的LMS中，异常甲基化率为50%（7/14）。结论　p16基因第一外显子启动子区5′CpG岛的异常甲基化是导致p16基因失活、蛋白缺如的重要基因外机制，并可能参与肿瘤的发生。

abstractsObjective　To observe the methylation status of p16 tumor suppressor gene in human soft tissue leiomyosarcoma (LMS) and its relationship with p16 protein expression. Methods　Methylation-specific PCR (MSP) assay was used to analyze the methylation status of 5′CpG island promoter / exon I region of p16 tumor suppressor gene in 38 LMS, 10 leiomyomas and 5 normal smooth muscle tissues. p16 expression in these tissues were examined by immunohistochemical assay. Results　Hypermethylation of p16 was observed in 23.7% (9/38) of cases, of which 7 with negative pl6 staining and 2 with faint positive staining. In the cases without protein expression, hypermethylation rate of p16 was 50% (7/14). Conclusions　Epigenetic change due to 5′CpG methylation is the main cause of inactivation of p16(INK4) gene which may be involved in tumor pathogenesis.