Tumor-Infiltrating CD8+ T Lymphocytes Associated With Clinical Outcome in Anal Squamous Cell Carcinoma

Background: The prognostic significance of tumor-infiltrating CD8(+) T lymphocytes in anal squamous cell carcinoma (SCC) remains unclear. We designed the study to investigate the association between CD8(+) T cells and clinical prognosis among anal SCC patients. Methods: The density of CD8(+) T cells was assessed by immunohistochemistry. The numbers of CD8(+) T cells were counted and their relationship with clinicopathological factors and survival was explored. Results: A strong positive correlation was noted between intratumoral and peritumoral CD8(+) T cells (r = 0.77, P< 0.001). High intratumoral and peritumoral CD8(+) T cells was associated with well tumor differentiation, early-stage diagnosis, and better prognosis (P< 0.05). Better disease-free survival rates were demonstrated in patients with high CD8(+) T cell density in intratumoral nest (P = 0.01); peritumoral stroma (P = 0.004); and both in combination (P = 0.01). High peritumoral CD8(+) T cell was associated with overall survival (P = 0.025). In HIV-infected patients, high CD8(+) T cell density also had association with disease-free survival (P< 0.05). Conclusions: High tumor-infiltrating CD8(+) T cell density showed the potential to indicate a favorable effect on prognosis and survival for anal SCC patients. (c) 2015 Wiley Periodicals, Inc.