Lymphocytic host response to oral squamous cell carcinoma: an adaptive T-cell response at the tumor interface.

Lymphocytic host response (LHR) in the Risk Model is histologically quantified as the density of lymphocytes at the tumor interface (Brandwein-Gensler in Am J Surg Pathol, 34:676-688, 1; in, Am J Surg Pathol 29:167-178, 2). It is classified as strong, intermediate or weak, and is inversely associated with the risk of decreased time to disease progression. In this study, we test the hypothesis that strong LHR corresponds to a greater degree of adaptive cytotoxic T cell response as compared to moderate LHR. We studied resection specimens of primary oral squamous carcinoma classified as having either strong (n = 16), intermediate (n = 20) or weak (n = 4) LHR. CD20+, CD4+, & CD8+ cells were detected by immunohistochemistry and quantified at 40× with a grid; counting the 10 fields with the most lymphocytes at the tumor interface and within tumors. Mean counts/tumor were analyzed by the 2-sided T-test. Statistically significant differences were observed for interface CD8 cells with respect to strong versus moderate LHR, strong versus weak LHR, and moderate versus weak LHR, and tumor infiltrating CD8 cells with respect to strong versus weak LHR. Statistically significant differences were also observed for interface CD4 cells with respect to strong versus weak LHR, and moderate versus weak LHR. Statistically significant differences in interface B cell counts were seen with respect to strong versus weak LHR, and moderate versus weak LHR. Decreased CD8+ T cells were significantly associated with higher stage at presentation (P = 0.005); a direct, but nonsignificant correlation was seen between decreased CD8+ T cells and decreased survival time. Immune response at the tumor interface correlates with an adaptive T cell response; the degree of cytotoxic CD8+ cells infiltrate can distinguish between strong and intermediate LHR at the interface of oral carcinomas.