胃癌组织中Raf激酶抑制蛋白的表达及临床意义

Expression of Raf kinase inhibitor protein in human gastric cancer and its clinical significance

目的探讨Raf激酶抑制蛋白（RKIP）在胃癌中的差异表达及临床意义。方法采用激光捕获显微切割技术（LCM）获得12例纯化的胃腺癌细胞（GAC）及其癌旁（〉5cm）胃黏膜上皮细胞（NGEC），应用^18O／^16O分别标记两种细胞样本酶切后的多肽混合物。结合纳升级液相色谱定量鉴定GAC和NGEC的差异表达蛋白质。免疫印迹法验证差异蛋白RKIP在胃癌中的表达。免疫组化检测RKIP蛋白在胃癌组织（118例）、癌旁胃黏膜组织（70例）、转移的淋巴结组织（35例）的表达。结果共筛选出78个差异表达蛋白质，其中RKIP蛋白表达水平在GAC中较NGEC明显下调（1：4．37）。免疫组化结果显示，RKIP蛋白表达与胃癌的浸润深度、TNM分期及淋巴结转移呈负相关，与分化程度呈正相关（P〈0．05）。结论胃癌组织中RKIP蛋白低表达可能影响胃癌的生物学行为。

Objective To investigate differential expression of Raf kinase inhibitor protein （RKIP） in gastric cancer and its clinical significance. Methods Pure gastric adenocarcinoma cells （GAC） and paracancerous gastric epithelial cells （NGEC） in 12 patient with gastric cancer were obtained using laser capture microdissection （LCM）. After trypsin digestion all specimens were labeled with ^18 O/^16O. Quantitatively identification of differentially expressed proteins between GCC and NGEC was conducted using Nano-HPLC-MS/MS. The expression of RKIP in GAC was determined by Western blotting. Immunohistochemistry （IHC） was used to detect the expression of RKIP in gastric cancer （n = 118）, non-cancerous mucosa tissues （n=70）and matched positive lymph node tissues （n = 35）. Results A total of 78 differentially expressed proteins were identified and RKIP was down expressed in GCC compared with NGEC （1 ： 4. 37）. IHC examination revealed that positive expression of RKIP in gastric cancer had negative relation with deeper invasion, TNM stage and lymphoid node metastasis, while it had positive relation with histological differentiation （P〈 0.05）. Conclusion Down regulation of RKIP in gastric cancer tissues might affect the biological behavior of gastric cancer.