expression of programmed death-1 ligand in renal cell carcinoma and its relationship with pathologic findings and disease-free survival

Background: renal cell carcinoma (rcc) is an invasive malignancy of kidney origin. the programmed death-1 ligand (pd-l1) with its receptor (pd-1) on t-cells can inactivate antitumor response and possibly lead to poor outcomes in patients with rcc. methods: our study assessed the expression of pd-l1 by immunohistochemical staining on 86 radical or partial nephrectomy samples with rcc diagnoses with diverse types, tumor grades, and stages. tumor specimens were collected from the pathology archive of 2014 - 2017 in sina hospital, tehran, iran. results: out of 86 studied rcc samples, 68 cases (79.1%) were clear cell types. pd-l1 expression was observed more in non-clear cell carcinoma samples than in clear cell carcinoma (p = 0.008). pd-l1 expression had significant relationships with nuclear grade and tumor necrosis (p = 0.025 and 0.010, respectively). however, pd-l1 expression was not correlated with tumor size, lymphovascular invasion, and sarcomatoid differentiation. the disease-free survival rate in patients with pd-l1 expression was significantly less than in patients with pd-l1 negative staining (p = 0.032). conclusions: according to our findings, pd-l1 could be regarded as an important biomarker with worse prognosis and aggressive clinicopathologic findings in patients with rcc.