The immune escape or tolerance of cancer cells is considered to be closely involved in cancer progression. Programmed death-1 (PD-1) is an inhibitory receptor expressed on activating T cells, and several types of cancer cells were found to express PD-1 ligand 1 (PD-L1) and ligand 2 (PD-L2).
In the present study, we investigated PD-L1/2 expression in papillary renal cell carcinoma (pRCC).
We found PD-L1 expression in 29 of 102 cases, but no PD-L2 expression was seen. PD-L1 expression was not significantly correlated with any clinicopathological factor, including progression-free survival and overall survival. The frequency of PD-L1-positive cases was higher in type 2 (36%) than in type 1 (22%) pRCC; however, there was no significant difference in the percentages of score 0 cases (p value = 0.084 in Chi-square test). The frequency of high PD-L1 expression cases was higher in type 2 (23%) than in type 1 (11%), and the frequency of high PD-L1 expression cases was higher in grade 3/4 (21%) than in grade 1/2 (13%). However, no significant association was found between PD-L1 expression and all clinicopathological factors in pRCC.
High expression of PD-L1 in cancer cells was potentially associated to highly histological grade of malignancy in pRCC. The evaluation of the PD-L1 protein might still be useful for predicting the efficacy of anti-cancer immunotherapy using immuno-checkpoint inhibitors, however, not be useful for predicting the clinical prognosis.
BMC urology. 2017 Jan 13*** epublish ***
Takanobu Motoshima, Yoshihiro Komohara, Chaoya Ma, Arni Kusuma Dewi, Hirotsugu Noguchi, Sohsuke Yamada, Toshiyuki Nakayama, Shohei Kitada, Yoshiaki Kawano, Wataru Takahashi, Masaaki Sugimoto, Motohiro Takeya, Naohiro Fujimoto, Yoshinao Oda, Masatoshi Eto
Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, 860-8556, Japan., Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, 860-8556, Japan. ., Department of Pathology and Cell Biology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan., Department of Urology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan., Department of Urology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan., Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.