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Background: 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).Methods: In the present study, we investigated PD-L1/2 expression in papillary renal cell carcinoma (pRCC).Result: 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.Conclusion: 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. [ABSTRACT FROM AUTHOR]

Since their discovery in the mid-1980s, interest in the immunological significance of γδ T cells has been subject to oscillations. The initial excitement over the unexpected discovery of a second T cell receptor (TCR) was followed by years of uncertainty as to the biological importance of these ambivalent T cells. Major breakthroughs led to the identification of specific and unique antigens for the γδ TCR and accumulating evidence now shows that γδ T cells play a major role in local immunosurveillance, thereby controlling tumorigenesis. Since 2004, biannual international γδ T cell conferences are held to bring together experts in basic and clinical γδ T cell research. To make accessible and synthesize the body of knowledge that has been put together, to date, we have organized a "Research Topic" on γδ T cells consisting of a collection of original articles and focused reviews written by leading experts in the field. The idea of this Research Focus was to present the current status and "hot topics" as well as clinical perspectives on γδ T cell research. [ABSTRACT FROM AUTHOR]