Implications of Programmed Death Ligand-1 Positivity in Non-Clear Cell Renal Cell Carcinoma

The purpose of this study was to assess the prognostic value of programmed death ligand-1 (PD-L1) positivity in a non-clear cell renal cell carcinoma (non-ccRCC) cohort. PD-L1 expression was evaluated by immunohistochemistry (IHC) using formalin-fixed paraffin-embedded (FFPE) specimens from 45 non-ccRCC patients with available tissue. PD-L1 positivity was defined as ≥1% of staining. Histopathological characteristics and oncological outcomes were correlated to PD-L1 expression. Cancer-specific survival (CSS) and recurrence-free survival (RFS) stratified by PD-L1 status were estimated using the Kaplan-Meier method. Median age was 58 years and median follow-up was 40 months. Non-ccRCC subtypes included sarcomatoid (n = 9), rhabdoid (n = 6), medullary (n = 2), Xp11.2 translocation (n = 2), collecting duct (n = 1), papillary type I (n = 11), and papillary type II (n = 14). PD-L1 positivity was noted in nine (20%) patients. PD-L1 positivity was significantly associated with higher Fuhrman nuclear grade (P = 0.048) and perineural invasion (P = 0.043). Five-year CSS was 73.2 and 83% for PD-L1 positive and negative tumors, respectively (P = 0.47). Five-year RFS was 55.6 and 61.5% for PD-L1 positive and negative tumors, respectively (P = 0.58). PD-L1 was expressed in a fifth of non-ccRCC cases and was associated with adverse histopathologic features. Expression of biomarkers such PD-L1 may help better risk-stratify non-ccRCC patients to guide treatment decisions and follow-up strategies.

Journal of kidney cancer and VHL. 2018 Oct 13*** epublish ***

Juan Chipollini, Mounsif Azizi, Charles C Peyton, Dominic H Tang, Jasreman Dhillon, Philippe E Spiess

Department of Genitourinary Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA., Department of Anatomic Pathology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.