KAI1/CD82 expression in nonsmall cell lung carcinoma is a novel, favorable prognostic factor: An immunohistochemical analysis

Abstract

BACKGROUND. The KAI1/CD82 gene, the product of which is a member of the transmembrane-4 superfamily, is a suppressor of metastasis; as a result, it is inversely associated with tumor progression and is a favorable prognostic factor in some tumors. This study was performed to determine the prognostic value of KAI1/CD82 protein levels in nonsmall cell lung carcinoma (NSCLC). In addition, levels of KAI1/CD82 expression in metastatic lesions were determined and compared with those in primary NSCLC lesions. METHODS. KAI1/CD82 expression in 200 NSCLC patients who underwent potentially curative surgery was immunohistochemically detected with C33, an anti-KAI1/CD82 monoclonal antibody. According to the degree of KAI1/CD82 positive cancer cells within the tumor tissue, each sample was classified as KAI1/CD82 positive, KAI1/CD82 reduced, or KAI1/CD82 negative. RESULTS. Sixty-five samples (32.5%) were KAI1/CD82 positive, 31 (15.5%) were reduced, and 104 (52%) were negative. There was no significant association between KAI1/CD82 expression and clinicopathologic factors, but patients who were positive for KAI1/CD82 expression had significantly favorable prognoses for overall survival (P = 0.0026) and disease free survival (DFS; P = 0.0007) compared with the other groups. In particular, among patients with adenocarcinoma, similar results were even more significant. In multivariate analysis, immunohistochemical KAI1/CD82 expression in patients with NSCLC was an independent prognostic factor for overall survival and DFS; in those with adenocarcinoma, it was an even more valuable factor. In some patients with NSCLC, especially those with adenocarcinoma, KAI1/CD82 expression levels in metastatic lesions were diminished compared with levels of expression in the primary lung lesions. CONCLUSIONS. The immunohistochemically determined level of KAI1/CD82 expression in NSCLC cells within tumor tissue appears to be a favorable prognostic factor for overall survival as well as DFS. The results of this study suggest that decreased KAI1/CD82 expression may be associated with tumor progression and enhanced metastatic potential in some patients with this disease.