RESUMO
INTRODUCTION: Squamous cell carcinoma of the skin (SCCs) is the second most common skin cancer, with continuously increasing incidence. Programmed cell death ligand 1 (PD-L1), programmed cell death 1 receptor (PD-1), and CD8 expression in primary SCCs have not been described in many studies. OBJECTIVE: We investigated the association between PD-L1, PD-1, CD8, and clinicopathological prognostic factors for recurrence, metastasis, and mortality of SCCs. PATIENTS AND METHODS: Immunohistochemically stained sections of 100 primary SCCs divided into two groups according to diameter of the tumors (<20 mm and >20 mm) were assessed. Recombinant rabbit anti-PD-L1 antibody [SP142] - C-terminal, rabbit monoclonal anti-PD1 antibody [NAT105], and FLEX Mono Mo A-Hu CD8, cl C8/144B, RTU were used. RESULTS: We did not establish statistically significant differences between PD-L1, PD-1, CD8 expression, and high-risk clinicopathological features - tumor size >20 mm, depth >6 mm, poor tumor cell differentiation, perineural/lymphovascular invasion, low/absent lymphocyte stromal reaction. CONCLUSIONS: In primary SCCs, the expression of PD-L1, PD-1, and CD8 are not associated with high-risk clinicopathological factors. We suggest that these immunohistochemical markers are more significant in advanced cases and metastatic tissues.