PD-L1 Expression in Thyroid Cancer and Its Correlation with Different Clinical-Pathological Parameters among Some Iraqi Population

Abstract

Background: thyroid cancer is the most common endocrine malignancy, particularly affecting women, and its incidence has been rising globally over the past two decades. Programmed cell death ligand 1 (PD-L1) is an immune checkpoint molecule known to contribute to tumour immune evasion. Its expression in thyroid cancer has been linked to tumour aggressiveness and poor prognosis, making it a potential biomarker and therapeutic target. Objectives: The aim of the Study is to investigate the expression of PD-L1in cases of thyroid cancer from Iraqi patients trying to correlate PD-L1 immunohistochemically expression and its correlation to clinical prognosis. Materials and Methods: retrospective cross-sectional study included 50 patients with thyroid cancer, whose formalin-fixed paraffin-embedded thyroid tissue blocks were retrieved from various hospitals in Hila. PD-L1 expression was evaluated immunohistochemically using the Tumour Proportion Score (TPS) method. Associations between PD-L1 expression and clinical features were analysed. Results: Among the 50 patients, 90% were female and 10% were male, mean age was 40.4 years. Papillary thyroid carcinoma was the most prevalent diagnosis (74%), PD-L1 was expressed in 46% of patients. PD-L1 expression was significantly associated with male gender (P < 0.001) and PTC histology (P = 0.003). There was no significant association between PD-L1 expression and age, tumour size, focality, or stage. Conclusions: PD-L1 could serve as a valuable biomarker for prognosis and potentially guide immunotherapy in thyroid cancer treatment.