Expression of PD-L1 in malignant soft tissue neoplasm and their correlation with clinicopathological parameters

Abstract

Objectives: Programmed death ligand-1 (PD-L1) expression in malignant epithelial neoplasms has been the subject of numerous studies; however, less data on its application to sarcomas are available. This research focused on the expression of PD-L1 and how it correlated with clinicopathological characteristics in soft tissue sarcomas. Materials and Methods: The anti-PD-L1 antibody and Ki-67 were stained in 50 cases of sarcoma that had been confirmed by biopsy and immunohistochemistry. The tumor cell percentage with complete or incomplete membrane staining was calculated. Sarcomas were categorized as positive (>1% of tumor cells with complete or incomplete membrane staining) or negative (≤1% of tumor cells with complete or incomplete membrane staining). The data were analyzed using Statistical Package for Social Sciences version 21.0. Statistical Analysis: Data were analyzed using Statistical Package for Social Sciences (SPSS, IBM Inc., United States), version 21.0. The independent sample t-test for continuous variables and the chi-square test for discrete variables were used to investigate the relationships between PD-L1 expression and clinicopathologic factors. A p-value less than 0.05 was considered statistically significant. Results: The soft tissue sarcomas showing marked pleomorphic morphology were significantly linked to positive PD-L1 expression than other subtypes of sarcomas (p = 0.042). Proliferation index grade III accounts for 62.5% of cases with positive PD-L1 expression, followed by proliferation index grade II with 25% cases and grade I with 12.5% cases. On comparing statistically, this difference was found to be significant (p = 0.013). A significant association was found between PD-L1 expression and the poor outcome of follow-up (p = 0.024). Conclusions: Our study showed a significant relationship between malignant soft tissue tumor positivity for PD-L1 and pleomorphic morphology, a higher proliferation index grade, and a poorer prognosis.