大肠癌组织RAB5A和CD44v9表达的意义

目的:探讨大肠癌组织RAB5A和CD44v9表达的意义．方法:应用SP免疫组化法检测43例大肠癌病理蜡块中RAB5A和CD44v9的蛋白质表达;取 60例大肠癌患者新鲜组织标本,提取RNA并逆转录合成cDNA,应用Real-time PCR法检测组织样本中RAB5A和CD44v9的基因表达;分析CD44v9和RAB5A的基因与蛋白质表达量与大肠癌分化及转移程度的相关性．结果:RAB5A蛋白表达阳性率为100％,阳性表达位于胞质和胞膜;CD44v9表达阳性率为 86．7％,阳性表达位于胞质;荧光定量PCR结果经熔解曲线分析各样本扩增产物的Tm值一致并与阳性对照的Tm值吻合．RAB5A cDNA 的表达量在高分化和中分化大肠癌组织中低于低分化大肠癌组织(P<0．01),在无淋巴结转移的大肠癌组织中低于有淋巴结转移的组织(P<0．01),而CD44v9 cDNA的表达趋势与 RAB5A相同;RAB5A与CD44v9的蛋白和基因表达均呈正相关(x2=14．532,P<0．01)．结论:RAB5A和CD44v9的表达与大肠癌的分化和转移有关,可能在跨膜信号传导和基质侵袭中共同发挥作用．

Significance of RAB5A and CD44v9 expression in colorectal cancer tissues

AIM: To investigate the expression of RAB5A and CD44v9 and their significances in colorectal cancer. METHODS: SP immunohistochemical method was adopted to detect the expression of RAB5A and CD44v9 proteins in the pathological paraffin sections from colorectal cancer (n = 43). RNA samples of 60 fresh tissues excised from patients with colorectal cancer were extracted and reversely transcribed into cDNAs, and then real-time polymerase chain reaction (RT-PCR) was used to detect the expression of RAB5A and CD44v9 genes. The correlations of RAB5A and CD44v9 expression with the differentiation and metastasis of colorectal cancer were analyzed. RESULTS: RAB5A protein was positively expressed in cytoplasm cell membrane with a rate of 100%, while CD44v9 protein was positively expressed only in cytoplasm with a rate of 86.7%. RT-PCR results showed that Tm of each sample was coincided with that of positive control by melting curve analysis. The expression of RAB5A cDNA was lower in highly and moderately differentiated cancers than that of poorly differentiated ones (P < 0.01), and it was also lower in cancers without lymph node metastasis than that with lymph node metastasis (P < 0.01). The expression of CD44v9 gene and protein were positively related to those of RAB5A (x2 = 14.532, P < 0.01). CONCLUSION: The expression of RAB5A and CD44v9 are correlated with the differentiation and metastasis of colorectal cancer, which may play important roles in the signal transduction across cellular membrane and matrix invasion.