程序性细胞死亡因子4在胃癌组织中的表达及临床病理学意义

Expression of programmed cell death factor 4 and its pathological significance in gastric cancer

目的：探讨胃癌组织中程序性细胞死亡因子4（programmed cell death 4，PDCD4）的表达及其临床病理学意义。方法：应用免疫组织化学和Western印迹杂交研究方法检测61例胃癌组织中PDCD4的表达，观察其与胃癌临床病理学参数之间的关系。结果：免疫组化染色显示，在正常胃组织中，阳性细胞比例均在80％以上。61例胃癌中，PDCD4低表达者（阳性细胞比例〈30％）占65．6％（40／61），高表达（阳性细胞比例介于30％～80％）者占34．4％（21／61）。Western印迹分析结果显示，同癌旁正常组织相比，所有胃癌组织PDCD4蛋白表达均明显下调。相关分析表明，PDCD4表达下调或缺失与肿瘤的不良分化相关，P〈0．01，而与性别、年龄厦肿瘤的TNM分期无关。结论：PDCD4蛋白在胃癌中多呈低表达，并与胃癌的分化程度有关，在胃癌的发生、发展过程中起重要作用。

OBJECTIVE： To investigate the expression of programmed cell death factor 4 （PDCD4） protein and its clinicopathological significance in gastric cancer. METHODS：PDCD4 expression in 5 fresh specimens of gastric cancer and relevant adjuvant non-cancerous tissue were detected by Western blot with PDCD4 specific antibody; immunohistochemistry was used to examine the expression of PDCD4 in 61 paraffin embedded specimens of gastric cancer, among which 26 specimens had adjacent normal gastric tissue. Correlations of PDCD4 expression with clinico-pathological data were analyzed. RESULTS： The expression of PDCD4 was significantly lower in all 5 fresh gastric cancer tissues than in non-cancerous tissues detected by Western blot. Compared with adjuvant normal gastric tissue （〉80% of positive cells）, low PDCD4 expression was shown in 61 gastric cancer tissues （〈30% of positive cells in 40 cases and 30%-80% of positive cells in 21 cases）. In the 21 cases that positive cells was between 30% and 80%, the rates of well, moderately, and poorly differentiated patients were 57.1%, 33.3% and 9.6%, respectively. However, in the 40 cases that positive cells was less than 30%, the rates of well, moderately, and poorly differentiated patients were 2.5%, 37.5% and 60%, respectively. In moderately and poorly differentiated patients, 68. 2% and 92. 3% showed positive cells less than 30%, however, only 7.7% well differentiated patients showed positive cells less than 30 %, indicating low PDCD4 level was associated with histological grade, P〈0. 01. There is no relationship between PDCD4 expression and other clinicopathological parameters including sex, age and TNM status. CONCLUSION： Progressive down-regulation of PDCD4 in gastric cancer is correlated with histological grade. PDCD4 may play an important role in occurrence and development of gastric cancer.