IMMUNOHISTOCHEMICALLY DETECTED EXPRESSION OF MOTILITY-RELATED PROTEIN-1 (MRP-1 CD9) IN LUNG ADENOCARCINOMA AND ITS RELATION TO PROGNOSIS/

Motility-related protein-1 (MRP-1)/CDP is a trans-membrane glycoprotei n closely associated with suppression of cell motility and reduced met astatic potential of some tumor cells. We currently report that, accor ding to the PT-POP method for MRP-1/CD9 gene expression, patients with low expression of MRP-1/CD9 in non-small-cell lung cancer, especially the adenocarcinoma type, showed short overall survival. Then, to dete rmine accurately the prognostic value of MRP-1/CD9 product levels in l ung-adenocarcinoma cells, we immunohistochemically investigated its ex pression in 132 lung-adenocarcinoma patients undergoing potentially cu rative surgery. Of these patients, 44 (33%) showed reduced expression of MRP-1/CD9 in cancer cells, and an inverse association was observed between its expression and factors associated with tumor progression, such as nodal involvement (p = 0.029) or stage (p = 0.028). Patients w ith reduced expression of MRP-1/CD9 showed a significantly worse progn osis in overall survival (p = 0.005) and disease-free survival (DFS; p < 0.0001) than those with stronger expression; and even among patient s with stage-I disease, similar results were obtained (overall surviva l, p = 0.038; DFS, p = 0.012). In a multivariate analysis, immunohisto chemical MRP-1/CD9-expression level was an independent prognostic fact or for DFS (p = 0.021), but not for overall survival (p = 0.572). Thus , immunohistochemical MRP-1/CD9-expression level solely in lung-adenoc arcinoma cells within the tumor tissue appears to be a prognostic fact or for DFS, and may be useful for detecting a high-risk sub-group of r ecurrence during the post-operative clinical course of the disease. (C ) 1997 Wiley-Liss, Inc.