P-selectin glycoprotein ligand-1 is diversely expressed in the primary tumour and venous thrombus of clear cell renal cancer and correlates with poor overall survival.

Introduction: In clear cell renal cell carcinoma (ccRCC), intravascular extension often results in neoplastic thrombus formation, impacting patient outcomes. Material and methods: We assessed P-selectin glycoprotein ligand-1 (PSGL-1) expression in the primary tumours and thrombi of 82 ccRCC patients. Results: Notably, PSGL-1 expression varied between tumour compartments, with higher prevalence in thrombus tumour cells (TC) and primary tumour-associated immune cells (TAIC). Positive TC PSGL-1 correlated with high-grade histology, while TAIC PSGL-1 was associated with tumour necrosis. Univariate survival analysis identified PSGL-1 positivity in TC of primary tumours and TAIC in thrombi as indicators of poorer overall survival. These findings suggest a potential role for PSGL-1 in the mediation of tumour thrombus formation, highlighting its relevance in biology of ccRCC. Conclusions: The increased expression of PSGL-1 in venous thrombi suggests its potential role in facilitating TC interactions with platelets and endothelium, potentially contributing to metastatic spread and worse outcomes. Understanding these expression patterns may aid in the development of novel therapeutic strategies and personalised treatment approaches for ccRCC patients.