PIWI蛋白与结肠癌预后的相关性

背景：PIWI蛋白为人类Argonaute蛋白家族的重要成员，与多种恶性肿瘤的发生、发展和预后相关。本课题组前期研究证实PIWIL1、PIWIL3、PIWIL4与结肠癌的发生、发展显著相关。目的：在前期研究的基础上进一步探讨PIWI蛋白与结肠癌预后的相关性。方法：选择183例携带随访信息的结肠癌病例，按癌组织与癌旁组织配对制成组织芯片，以免疫组化方法检测PIWIL1、PIWIL2、PIWIL3、PIWIL4表达。采用Spearman秩相关系数分析PIWI蛋白表达与结肠癌临床病理指标间的相关性；Kaplan-Meier生存曲线和log-rank检验以及Cox比例风险模型分析PIWI蛋白表达与结肠癌预后间的相关性。结果：PIWIL1-4在结肠癌组织胞质中的表达均显著高于癌旁组织（P=0.000），且与肿瘤T分期呈正相关（P〈0.01）。生存分析显示癌组织PIWIL1低表达者总生存期显著长于高表达者（P=0.036），但PIWIL1并非结肠癌预后的独立相关因素。结论：PIWI蛋白参与了结肠癌的发生、发展过程，PIWIL1有望作为结肠癌预后的重要分子标记物。

Correlation between PIWI Proteins and Prognosis of Colon Cancer

Background： As an important member of human Argonaute family, PIWI proteins have been detected in various malignancies and were associated with their genesis, development and prognosis. Our previous study confirmed that PIWIL1, PIWIL3 and PIWIL4 were significantly correlated with the genesis and development of colon cancer. Aims： To further explore the correlation between PIWI proteins and prognosis of colon cancer on the basis of previous research. Methods： A total of 183 colon cancer patients with follow-up information were enrolled. Paired cancerous and adjacent non-cancerous tissues were collected to construct tissue microarrays and expressions of PIWIL1, PIWIL2, PIWIL3 and PIWIL4 were determined by immunohistochemistry. Correlation of expressions of PIWI proteins with clinicopathological factors was analyzed by Spearman rank correlation coefficient, and the correlation with prognosis was assessed by Kaplan-Meier curve, log-rank test and Cox proportional hazard model. Results： Expressions of PIWIL1-4 in cytoplasm were significantly higher in cancerous tissue than in adjacent non-cancerous tissue （P=0.000）, and significant positive correlation was observed between cytoplasmic expressions of PIWIL1-4 in cancerous tissue and T stage of tumor （P〈0.01）. Survival analysis demonstrated that elevated PIWIL1 expression in cancerous tissue predicted a poorer overall survival when compared with lower PIWIL1 expression （P=0.036）, but this protein was not an independent prognostic factor for colon cancer. Conclusions： PIWI proteins are involved in the genesis and development of colon cancer, and PIWIL1 might serve as an important molecular biomarker for prognosis of colon cancer.