Maria Luiza Diniz de Sousa Lopes1, Amanda Katarinny Goes Gonzaga1, Carla Mosconi2, Gustavo Martelli Palomino3, Elismauro Francisco Mendonça4, Aline Carvalho Batista2, Éricka Janine Dantas da Silveira5. 1. Post-Graduate Program in Oral Pathology, Department of Dentistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil. 2. Department of Stomatology (Oral Pathology), Dental School, Federal University of Goiás, Goiânia, Brazil. 3. Division of Rheumatology, Faculty de Medicine, University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil. 4. Department of Stomatology (Oral Pathology), Dental School, Federal University of Goiás, Goiânia, Brazil; Araújo Jorge Hospital, Association of Cancer Combat of Goiás, Division of Head and Neck and Department of Stomatology (Oral Pathology), Dental School, Federal University of Goiás, Goiânia, Brazil. 5. Post-Graduate Program in Oral Pathology, Department of Dentistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil. Electronic address: ericka.janine@yahoo.com.br.
Abstract
OBJECTIVES: Programmed death ligand-1 (PD-L1) and human leukocyte antigen-G (HLA-G) are considered immune checkpoint molecules that inhibit T-cell effectiveness, contributing to tumor immune escape. This study investigated PD-L1, HLA-G, CD8, and granzyme B (GrB) expression at different stages of lip carcinogenesis. DESIGN AND RESULTS: Forty cases of lip squamous cell carcinoma (LSCC), 55 actinic cheilitis (AC), and 10 healthy lip mucosa (HLM) were submitted to immunohistochemistry. Semiquantitative (PD-L1, HLA-G), and quantitative (CD8, GrB) analysis were performed. PD-L1 and HLA-G expression in neoplastic cells/keratinocytes and stroma/connective tissue was significantly higher in LSCC and AC, compared to HLM (p<0.05). PD-L1 was not associated with clinicopathological features of the lesions. HLA-G expression by malignant cells was significantly higher in LSCCs with distant metastasis (p = 0.041).CD8+ and GrB+ cell numbers progressively increased from HLMs to LSCC, with AC exhibiting intermediate numbers (p<0.01). Most LSCCs showed coexistence of PD-L1+ and CD8+ cells (72.5%). PD-L1 was directly correlated to CD8+ and GrB+ lymphocytic infiltration in LSCCs (p<0.05). Low cytotoxic immune response was associated with lymph node metastasis in LSCC (p<0.05). CONCLUSIONS: PD-L1 and HLA-G-mediated immune evasion mechanisms are likely to occur from early pre-malignant to advanced malignant stages of lip carcinogenesis, which might provide a rationale for therapeutic blockade of these pathways. PD-L1 expression in LSCCs was correlated with the cytotoxic markers, suggesting that PD-L1 may appear as an escape mechanism in response to an active antitumor response.
OBJECTIVES:Programmed death ligand-1 (PD-L1) and human leukocyte antigen-G (HLA-G) are considered immune checkpoint molecules that inhibit T-cell effectiveness, contributing to tumor immune escape. This study investigated PD-L1, HLA-G, CD8, and granzyme B (GrB) expression at different stages of lip carcinogenesis. DESIGN AND RESULTS: Forty cases of lip squamous cell carcinoma (LSCC), 55 actinic cheilitis (AC), and 10 healthy lip mucosa (HLM) were submitted to immunohistochemistry. Semiquantitative (PD-L1, HLA-G), and quantitative (CD8, GrB) analysis were performed. PD-L1 and HLA-G expression in neoplastic cells/keratinocytes and stroma/connective tissue was significantly higher in LSCC and AC, compared to HLM (p<0.05). PD-L1 was not associated with clinicopathological features of the lesions. HLA-G expression by malignant cells was significantly higher in LSCCs with distant metastasis (p = 0.041).CD8+ and GrB+ cell numbers progressively increased from HLMs to LSCC, with AC exhibiting intermediate numbers (p<0.01). Most LSCCs showed coexistence of PD-L1+ and CD8+ cells (72.5%). PD-L1 was directly correlated to CD8+ and GrB+ lymphocytic infiltration in LSCCs (p<0.05). Low cytotoxic immune response was associated with lymph node metastasis in LSCC (p<0.05). CONCLUSIONS:PD-L1 and HLA-G-mediated immune evasion mechanisms are likely to occur from early pre-malignant to advanced malignant stages of lip carcinogenesis, which might provide a rationale for therapeutic blockade of these pathways. PD-L1 expression in LSCCs was correlated with the cytotoxic markers, suggesting that PD-L1 may appear as an escape mechanism in response to an active antitumor response.