Immunohistochemical Study of KAI1, a Tumor Metastasis Suppressor Gene, Expression in Rectal Cancer

ABSTRACT

PURPOSE: KAI1/CD82 gene is a recently identified metastasis suppressor gene on human chromosome 11p11.2. Alteration to or reduction of this molecule may allow tumor cells to invade the surrounding tissue and blood vessels. Decreased KAI1 expression seems to be involved in the progression of human prostate, lung and possibly breast cancer, and recently has been demonstrated in several colorectal cell lines. The aim of this study is to determine whether the gene is altered to investigate it in the progression and metastatic process of rectal carcinoma. In addition, its prognostic significance is also evaluated. METHODS: Total 108 tumor samples from primary, metastatic rectal carcinoma were prepared for immunohistochemical study with an anti-KAI1 polyclonal antibody. To analysis the correlation between KAI1 expression and clinicopathological parameter and to evaluate for relation expression and survival. RESULTS: Decrease of KAI1 protein expression was associated with the depth of invasion of tumor (P < 0.0001) and node metastasis (P < 0.05). Liver metastasis showed reduced KAI1 expression when compared with their corresponding primary tumor. Although there was a trend for deteriorating survival from patients with KAI1-positive tumors to those with KAI1-decreased and -negative tumors, it was not significant statistically (P CONCLUSIONS: KAI1 may play a role in the malignant progression of rectal carcinoma through the down-regulation of expression. KAI1 might influence the metastatic ability of human rectal cancer. And its prognostic significance needs further investigation with a larger number of cases.