Analysis of T-cell receptor expressing lymphocytes infiltrating squamous cell carcinomas of the upper aerodigestive tract.

T-lymphocytes expressing T-cell receptors (TCRs) of the gamma/delta type have been suggested to play an important role in mucosal defense against infection and neoplastic transformation. In this study, an immunohistochemical investigation was performed on the distribution of alpha/beta and gamma/delta TCRs among tumor-infiltrating lymphocytes. Thirteen patients with squamous cell carcinomas of the upper aerodigestive tract were studied, using monoclonal antibodies and an avidin-biotin-peroxidase technique. Most of the T-cells had an alpha/beta TCR. Only 1.6% of the T-cells within the cancer tissue and 1.2% of the T-cells in the parenchyma adjacent to the cancer tissue expressed gamma/delta TCRs. These results are consistent with the results of similar studies in bronchial and breast carcinomas. Biopsies from normal oral mucosa in nine healthy individuals showed that 1.3% of the T-cells within the epithelium and 1.0% of those in the lamina propria adjacent to the epithelium expressed gamma/delta TCRs. Quantitatively the results do not support the theory that gamma/delta T-cells play an important role in the immunological response against cancer tissue in the mucosa of the upper aerodigestive tract. The functional role of these cells in the mucosa and in response to carcinomas is, however, still uncertain.