大肠癌及其肝转移组织骨桥蛋白mRNA的表达

目的　检测骨桥蛋白mRNA在大肠癌及其肝转移灶中的表达差异和蛋白定位 ,并探讨其在大肠癌肝转移发生发展中的意义。方法　提取 4 4例大肠癌及癌旁正常组织及 2 0例大肠癌肝转移组织RNA ,采用实时荧光定量PCR(FQ PCR)法检测其中骨桥蛋白mRNA的表达。用免疫组织化学法行骨桥蛋白的组织学检测。根据FQ PCR以CT 值为标准 ,所得数值与实际表达量对数值呈反比的原理 ,以骨桥蛋白CT GAPDHCT 的比值来评价不同组织骨桥蛋白的表达。结果　骨桥蛋白mRNA表达在大肠癌肝转移灶中表达最高 (1 0 7± 0 10 ) ,在原发大肠癌组织中次之 (1 15± 0 14 ) ,而在癌旁正常大肠组织中表达最低 (1 32± 0 18) ;统计分析差异有显著意义 (t=5 81,P =0 0 0 0及t=2 .12 ,P =0 .0 38)。免疫组织化学结果表明 ,骨桥蛋白定位于大肠癌细胞及肝转移灶旁正常肝细胞的细胞质。结论　骨桥蛋白mRNA在大肠癌中的表达高于正常组织 ,而在大肠癌肝转移组织中表达更高 ,骨桥蛋白定位于大肠癌细胞质。这提示骨桥蛋白与大肠癌的浸润转移有关 ,可作为大肠癌肝转移的预测指标之一。

Expression of osteopontin mRNA and its protein in colorectal cancer and liver metastatic tissues

OBJECTIVE: To investigate the expression of osteopontine (OPN) in colorectal cancer and liver metastatic tissues and the significance of OPN in tumorigenesis and liver metastasis of colorectal cancer. METHODS: The expression of OPN mRNA in 44 samples of colorectal cancer tissues and adjacent normal tissues and 20 samples of liver metastatic tissues was examined by FQ-PCR, using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as internal standard. S-P immunohistochemical method was utilized to detect the OPN protein in colorectal cancer and liver metastasis tissues. On the principle that the C(T) value is in inverse proportion to the log value of original copy number of target sequence, OPN C(T)/GAPDH C(T) was used to evaluate the mRNA expression level in different tissues. RESULTS: The OPN mRNA levels in colorectal cancer tissues were 0.85 approximately 1.47 (kappa +/- s = 1.15 +/- 0.14 ), significantly higher than those in adjacent normal tissues (0.94 approximately 1.47,kappa +/- s =1.32 +/- 0.18) and lower than those in liver metastatic tissues (0.92 approximately 1.30,kappa +/- s =1.07 +/- 0.10) (t =5.81, P =0.00 and t = 2.12,P =0.038), Immunohistochemistry showed that OPN protein was localized in the cytoplasm of colorectal cancer cells, metastatic cancer cells, and normal hepatocytes around metastatic tissue, but not in the normal colorectal tissues around the primary cancer and normal hepatocytes in persons without colorectal cancer. CONCLUSION: The expression of OPN mRNA is the highest in liver metastatic tissues, moderate in primary colorectal cancer tissues, and lowest in adjacent normal tissues of the metastatic liver cancer. OPN protein is located in cytoplasm of colorectal cancer cells. OPN is a potential marker for liver metastasis of colorectal cancer.