Abstract
Liposarcomas, the most common subtype of soft tissue sarcomas, show variable biological behavior and therapeutic response. Programmed death-ligand 1 (PD-L1) and cytotoxic T lymphocyte marker CD8 have been implicated in tumor immune evasion and prognosis in various malignancies, while Maspin, a tumor suppressor, has shown a negative prognostic impact in sarcomas. This study aimed to investigate the clinicopathological significance of PD-L1, CD8, and Maspin expression in liposarcomas. A retrospective analysis of 42 liposarcoma cases diagnosed between 2016 and 2023 was conducted. Immunohistochemical staining for PD-L1 (using DAKO 22C3 and 28-8 clones), CD8, and Maspin was performed. PD-L1 expression was assessed using the tumor proportion score (TPS) and tumor cell score (TC). CD8 expression was evaluated using an H-score, and Maspin positivity was assessed based on subcellular localization. Correlations with clinicopathological parameters were statistically analyzed using chi-squared and Fisher's exact tests. Most liposarcomas exhibited low PD-L1 expression (<10%), but increased PD-L1 levels correlated with poor differentiation (G3), higher CD8 infiltration (H-score > 10%), and cytoplasmic Maspin positivity. Statistically significant associations were found between high PD-L1 expression and high CD8 infiltration (p = 0.007 for 22C3; p = 0.0331 for 28-8) and between PD-L1 positivity and Maspin expression (p = 0.003 for 22C3; p = 0.0113 for 28-8). CD8 infiltration was generally low across cases, and PD-L1 expression in inflammatory cells was noted predominantly in tumors with higher PD-L1 TPS/TC scores. High PD-L1 expression in liposarcomas is associated with poor tumor differentiation, increased CD8 infiltration, and Maspin positivity, suggesting an immune-evasive phenotype. Despite low overall expression rates, PD-L1 could serve as a prognostic biomarker and a potential target for immunotherapeutic strategies in liposarcomas. Further studies are necessary to standardize PD-L1 assessment and explore effective immunotherapy approaches for these tumors.