The Clinical And Experimental Research On Metastasis Suppressor Gene KAI1/CD82 In Colorectal Carcinoma

In order to research the cyto-molecular mechanism of invasion and metastasis in colorectal carcinoma as well as to evaluate its clinical significance, the mRNA transcription levels of KAI1/CD82 gene were assayed in 30 samples of colorectal carcinoma (T), tissue surrounding rumor, 2cm(P2), 5cm(P5) far from tumor, and distal normal tissue colorectal tissue (N) collected from surgical procedure with quantitative reverse transcription polymerase chain reaction (Q-RT-PCR). KAI1/CD82 protein expression of each sample was determined separately with flow cytometry and immunohistochemistry. These data were analyzed statistically and compared with the clinico-pathological factors. The results showed that:1. The mRNA transcription level of KAI1/CD82 in colorectal carcinoma (T) was significantly inverse-correlated to lymph metastasis and moderately associated with tumor stage.2. The expression levels of KAI1/CD82 protein determined with flow cytometry were moderately correlated to lymph metastasis and tumor stage, separately.3. The data (KAI1 mean score, KMS) obtained through immunohistochemical examination appeared significant differences among four sites of specimens. The KAI1/CD82 protein expression level in colorectal carcinoma were significantly lower than in the tissues of 2cm (P2), 5cm (P5) and distal site (N), meanwhile the expression in P2 was significantly lower than it in N.34. The KAI1/CD82 protein expression levels (KMS) in T determined with immunohistochemical method individually showed the significantly, moderately and slightly correlative to tumor grade, lymph metastasis and stage.5. The KAI1/CD82 mRNA transcription level was significantly correlative to its corresponding flow cytometric assay result. In contrast, no correlation to the result of immunohistochemical examination (KMS) was found. The KAI1/CD82 protein expression levels obtained through two assay methods were differential.The conclusions are that:1. The KAI1/CD82 mRNA transcription and protein expression levels are inversely correlated with lymph metastasis and tumor stage. The expressions of KAI1/CD82 gene are gradually coming lower with lymph node metastasis and tumor progression. Down-regulation of KAI1/CD82 gene is associated with the invasion and metastasis in colorectal carcinoma.2. The KAI1/CD82 transcription and protein expression levels might be a major molecular event and play an important role in progression of this malignancy.3. The KAI1/CD82 protein may be a valuable biological marker in metastasis and prognosis of colorectal carcinoma.4. The significant lower expression of KAI1/CD82 immunohistochemical assay in P2 to N suggests that this kind of alteration may appear not only in primary tumor but also in tissue surrounding tumor. To study the KAI1/CD82 protein expression in tissue surrounding tumor could be useful to clinical evaluation.