Evaluation of PD-L1 expression and clinicopathological features in clear cell TYPE renal cell carcinoma

Renal cell carcinoma (RCC) is diagnosed in more than 400,000 people each year and accounts for approximately 3% of all malignancies. Clear cell RCC (CCRCC) is the most common subtype of RCC. While the 5-year survival rate of BHRCC is 92% in organ-localized disease, it decreases to 12% in cases with distant metastases. Conventional clinicopathological parameters are used to predict the prognosis of RCC, but these parameters are insufficient in predicting the prognosis and choosing the treatment agent. Conventional clinicopathological parameters are used to evaluate the prognosis of CCRCC, but these parameters are insufficient in predicting the prognosis and choosing the treatment agent. Many immunohistochemical biomarkers have been investigated as potential prognostic factors, but no reliable marker has been identified for routine use today. Due to the increasing interest in immune checkpoint inhibitors in recent years, the effect of these pathways has gained importance in CCRCC cases. There are many studies investigating the effect of programmed cell death ligand-1 (PD-L1), which has an important role in immune control pathways, on prognosis in CCRCC, and there are conflicts between studies. 101 cases diagnosed with BHRCC from radical nephrectomy materials in Tokat Gaziosmanpaşa University Faculty of Medicine, Department of Pathology between 2010 and 2019 were included in the study. The relationship between clinicopathological parameters, survival parameters and PD-L1 expressions of these cases was examined. In our study, when PD-L1 expression in tumor cells was evaluated separately in two groups as any membranous expression and 5% or more membranous expression, a significant increase was found in the incidence of v renal capsule invasion in both categories (p=0.023 and p=0.039, respectively). In addition, when we accepted any membranous expression as positive, a significant increase was found in the rate of distant metastasis in PD-L1 positive cases. (p=0.027). High WHO/ISUP nuclear grade, large tumor size, lymphovascular invasion, perirenal fat tissue invasion and renal vein invasion detection rates were observed to increase in CCRCC cases with PD-L1 expression, but no statistical significance was found. We think that the reason for this is related to the low number of PDL-1 positive cases. Considering our clinicopathological data, a significant correlation was found between tumor diameter, tumor T stage, nuclear grade, necrosis, lymphovascular invasion, renal sinus invasion, renal capsule invasion, perirenal fat tissue invasion, renal vein invasion and metastasis (Log Rank p<0,05). In conclusion, we found that the clinicopathological data of our cases were compatible with the literature. However, our study results suggest that the presence of PD-L1 expression in CCRCCs may be associated with poor prognostic factors, especially distant metastasis. Keywords: Renal cell carcinoma, Clear cell renal cell carcinoma, Programmed cell death ligand-1