Tumor immune microenvironment in primary and metastatic papillary renal cell carcinoma.

Among renal cell carcinoma (RCC) the tumor immune microenvironment has been best characterized in clear cell RCC. In this study we investigated the expression of several immune markers including PD-L1, FOXP3, and CD8 in primary and metastatic papillary RCC. Three tissue microarrays were constructed from 78 cases with primary papillary RCC and paired metastatic tumor (24 cases) from 78 patients treated between 1982 and 2014. Immunohistochemistry analysis was performed using commercially available antibodies for PD-L1 (clone E1L3N), FOXP3, CD8 and Ki-67. Markers expression level in tumor and or associated immune cells was analyzed by tissue type (non-tumor vs. primary tumor vs. metastatic tumor) and correlated to clinicopathologic features and outcome. We found PD-L1 expression in up to one quarter of primary and metastatic papillary RCC. On univariate analysis CD8/FOXP3 ratio > 1 was associated with favorable outcome, whereas papillary RCCs with high numbers of dual CD8/Ki-67 positive lymphocytes showed an increased likelihood for tumor progression, overall and cancer-related mortality. The association of CD8/FOXP3 ratio > 1 and high count of CD8/Ki-67 with outcome remained significant on multivariate analysis when adjusting for stage, grade and patient's age. This article is protected by copyright. All rights reserved.

Histopathology. 2019 Sep 07 [Epub ahead of print]

Marie-Lisa Eich, Alcides Chaux, Maria Angélica Mendoza Rodriguez, Gunes Guner, Diana Taheri, Maria Del Carmen Rodriguez Pena, Rajni Sharma, Mohamad E Allaf, George J Netto

Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA., Department of Scientific Research, School of Postgraduate Studies, Norte University, Asunción, Paraguay., Department of Pathology, Johns Hopkins University, Baltimore, MD, USA., Department of Urology, Johns Hopkins University, Baltimore, MD, USA.