Abstract
Prior work in our laboratory has shown that the expression of an epithelial antigen identified by the monoclonal antibody A9 is amplified in squamous carcinoma cell lines and that the intensity of expression is related to aggressive cell growth in vitro and in the nude mouse (1). To determine if alterations in expression of normal epithelial antigens are related to the biological behaviour of squamous cell carcinoma in man, the expression of the A9 antigen and of normal A, B and H blood group antigens in primary tumor tissue sections from 41 patients with cancer of the oral cavity and oral pharynx was analyzed. The majority of these patients had stage III (19/41) or stage IV (17/41) tumors. Antigen expression was analyzed with respect to traditional histologic features and disease-free survival. Median follow-up was 13 months (range 1—53 months). Disease-free survival was decreased (median 8.7 months) in patients with tumors that had high A9 expression compared to patients with low A9 expression (p =. 1328). A stronger association was found for loss of blood group and early relapse. Patients whose tumors failed to express blood group antigen had a median disease-free survival of only 5 months. This was significantly less than that of patients whose tumors retained normal blood group expression (median disease-free survival interval not yet reached) (p =. 018). Variations in the pattern of A9 and ABH blood group antigen expression were independent of T class, N class, tumor stage, keratinization and growth pattern. There was an association of strong A9 expression with tumor grade (differentiation) (p ±. 01). Our observations indicate that these immunohistological staining characteristics are independent of most traditional histologic and clinical grading systems and may have independent prognostic importance in oral cancer. Further study of larger patient populations that include more patients with earlier stage disease are necessary to confirm these findings.