Tiam1、Rac1在评估大肠癌远隔脏器转移中的意义

Significance of Tiam1 and Rac1 expression in assessing remote organ metastasis of colorectal cancer

目的:观察人大肠癌和癌旁正常大肠黏膜组织中T淋巴瘤侵袭转移诱导因子1(Tiam1)和RacGTP酶激活蛋白1(Rac1)的表达,并探讨其与大肠癌根治术后发生远隔脏器转移的相关性.方法:应用SP免疫组织化学法检测87例大肠癌及40例癌旁正常组织标本中Tiam1/Rac1的表达情况;应用竞争性RT-PCR检测上述标本中Tiam1 mRNA的表达情况;应用配体沉淀法检测上述标本中Rac1蛋白活性.结果:Tiam1/Rac1在大肠癌细胞胞质内呈阳性染色.Tiam1 mRNA在大肠癌中表达明显增强(0.6±0.02vs0.24±0.02,P<0.0005),并且在术后发生远隔转移患者中的表达要高于未发生远隔转移者(0.91±0.02vs0.52±0.02,P<0.0005).Rac1蛋白活性的表达情况与Tiam1一致,在大肠癌中表达高于正常黏膜(0.17±0.01vs0.07±0.05,P<0.0005),并且在有远隔转移的大肠癌组织中活性要高于无远隔转移者(0.25±0.02vs0.15±0.01,P<0.0005).对于不同分化程度的大肠癌组织,Tiam1/Racl的含量均没有统计学差异(0.63±0.04,0.60±0.04,0.57±0.04,P=0.613;0.18±0.06,0.17±0.05,0.15±0.05,P=0.558).结论:Tiam1/Racl是大肠癌根治术后患者发生远隔转移的正性因子,可以作为预测大肠癌根治术后患者发生远隔脏器转移的有效指标.

AIM：To observe the expression of T lymphoma invasion and metastasis-inducing factor1（Tiam1） and Rac GT-Pase activating protein1（Rac1） in colorectal cancer and to investigate the relationship between Tiam1/Rac1 expression and remote organ metastasis of postoperative colorectal cancer.METHODS：Tiam1/Rac1 expression in 87 colorectal cancer specimens and 40 tumor-adjacent colorectal tissue specimens was detected by immunohistochemistry.Tiam1 mRNA expression was detected by competitive RT-PCR.Activity of Rac1 protein was detected by precipitation method.RESULTS：Tiam1 and Rac1 were positivelystained in colorectal tissue,and positive signals were mainly distributed in the nucleus.Tiam1 mRNA expression was significantly increased in colorectal cancer（0.6 ± 0.02 vs 0.24 ± 0.02,P 0.0005）,and Tiam1 expression was higher in postoperative patients with remote organ metastasis than in those without remote organ metastasis（0.91 ± 0.02 vs 0.52 ± 0.02,P 0.0005）.Activity of Rac1 was also significantly increased in colorectal cancer tissue（0.17±0.01 vs 0.07±0.05,P 0.0005） and was higher in postoperative patients with remote organ metastasis than in those without remote organ metastasis（0.25 ± 0.02 vs 0.15 ± 0.01,P 0.0005）.There was no significant correlation between Tiam1/Rac1 expression and tumor differentiation in colorectal cancer（0.63 ± 0.04,0.60 ± 0.04,0.57 ± 0.04,P = 0.613;0.18 ± 0.06,0.17 ± 0.05,0.15 ± 0.05,P = 0.558）.CONCLUSION：Tiam1 and Rac1 expression positively correlates with remote organ metastasis of colorectal cancer and can be used to predict remote organ metastasis of postoperative patients with colorectal cancer.