TY - JOUR T1 - PD-L1 Expression, T-lymphocyte Subpopulations and Langerhans Cells in Cutaneous Squamous Cell Carcinoma and Precursor Lesions JF - Anticancer Research JO - Anticancer Res SP - 3439 LP - 3448 DO - 10.21873/anticanres.15131 VL - 41 IS - 7 AU - ARISTEA STRAVODIMOU AU - VASILIKI TZELEPI AU - STAVROS BALASIS AU - SOPHIA GEORGIOU AU - HELEN PAPADAKI AU - ATHANASIA MOUZAKI AU - MARIA MELACHRINOU AU - ELENI P. KOUREA Y1 - 2021/07/01 UR - http://ar.iiarjournals.org/content/41/7/3439.abstract N2 - Background/Aim: The role of immune cells and PD-L1 in cutaneous squamous carcinogenesis is unclear. This study examines T-cell populations, Langerhans cells (LCs) and PD-L1 in invasive squamous cell carcinoma (inSCC), adjacent precursors and normal skin (NS) to investigate their participation in tumorigenesis. Materials and Methods: Cases of cutaneous inSCC with adjacent precursors (n=125) were selected. In situ SCC (isSCC) and actinic keratosis (AK) were observed in 53 and 123 cases, respectively, whereas NS was present in 123 lesions. Immunohistochemistry was performed for CD3, CD8, Foxp3, CD1a and PD-L1. Results: T-cells, LCs and PD-L1 gradually increase during the evolution from AK to isSCC and inSCC, with statistical significance between all lesions, except for CD3+ and CD8+ cells between isSCC and inSCC. Epithelial PD-L1 expression correlates with tumor diameter and thickness. Conclusion: The progressive increase of T-cells, LCs and PD-L1 in cutaneous squamous carcinogenesis provides rationale for immunotherapy and identification of predictive biomarkers. ER -