胃癌p21^WAF1基因表达与组蛋白乙酰化关系的初步研究

目的：探讨胃癌组织p21^WAF1基因表达与组蛋白乙酰化的关系。方法：利用RT—PCR对53例原发性胃癌的癌组织、癌旁组织和正常胃黏膜的p21^WAF1 mRNA表达进行分析；同时对其中p21^WAF1 mRNA表达失活或表达量不足癌旁和正常黏膜的1／2的7例患者进行乙酰化组蛋白免疫印迹分析。结果：①胃癌组织中的p21^WAF1表达率和表达值均显著低于正常胃黏膜和癌旁组织。②p21^WAF1表达水平在分化较好和分化较差的胃癌组织间差异没有显著性（P〉0．05），但在不同浸润深度及有／无淋巴结转移的胃癌组织中差异具有显著性（P〈0．05，P〈0．01）。③p21^WAF1 mRNA表达失活或表达量不足癌旁和正常黏膜的1／2的7例患者中有5例（5／7，71.43％）总染色质乙酰化组蛋白H3表达水平明显低于其相应的癌旁和正常黏膜，甚至在检测水平以下。结论：胃癌组织p21^WAF1的表达降低至少部分归因于组蛋白乙酰化水平的低下。

Preliminary study on the relationship of p21WAF1 gene expression in gastric cancer and histone acetylation

Objective：To investigate the relationship between p21^WAF1 gene expression and histone acetylation in gastric cancer. Methods： p21^WAF1 gene expression of cancer tissue, para-focus of cancer and normal tissue in 53 cases with primary gastric cancer were analyzed with RT-PCR, meanwhile, histone acetylation in 7 cases with p21^WAF1 mRNA non-expression or expression less than half of para-focus of cancer and normal tissue were analyzed with Western blot hybridization. Results：（1） Both p21^WAF1 expression ratio and value of gastric cancer were lower than those of para-focus of cancer and normal tissue. （2） p21^WAF1 expression level had no difference between well-differentiated and poorly-differentiated gastric cancer （P〉0.05）, but there was significantly difference in different invasion depth and had none lymph node metastasis （P〈0.05, P〈0.01）. （3） The expression of acetylated histone-H3 in total chromatin of 5 cases （5/7, 71.43%） was significantly lower than those of para-focusofcancer and normal tissue corresponding to them, even under detective level. Conclusion： The lower expression of p21^WAF1 in gastric cancer is partly due to lower level of histone acetylation.