FODRIN IMMUNOLOCALIZATION IN EPITHELIAL TUMORS

The first application of a monoclonal antibody (mAb clone 101AA6) to t he membrane skeletal protein alpha-fodrin (nonerythroid alpha-spectrin ) in paraffin-embedded sections of adenocarcinomas (41 cases) and squa mous cell carcinomas (28 cases) from a variety of sites is reported. N onlesional glandular epithelial cells displayed a basolateral asymmetr ical cell membrane localization of fodrin. There was also apical stain ing in epithelial cells of the colon. In contrast, neoplastic cells re vealed strong, often fragmented, circumferential membrane staining. In addition, there was distinct cytoplasmic staining of fodrin that was clearly granular in anaplastic tumor cells. There is a suggestion that this staining pattern becomes accentuated with increasing grades of a naplasia, being most prominent in the advancing fronts of tumors and w ithin foci of poor differentiation in otherwise well-differentiated tu mors. Strong cytoplasmic staining for fodrin, circumferential membrane staining with fragmentation, and, less frequently, loss of membrane s taining correlated with loss of epithelial tumor cell cohesiveness or transformation to spindle shapes. In comparison with their nonneoplast ic counterparts, neoplastic epithelial cells showed elevated levels of fodrin staining regardless of tumor type. This overextending and redi stribution of fodrin may have important implications in tumor cell adh esiveness and metastatic potential.