Programmed Death Ligand 1; An Immunotarget for Renal Cell Carcinoma

Document Type: Research Articles

Authors

1 Department of Physiology, Teynampet, India.

2 Department of Pathology, Teynampet, India.

3 Apollo speciality hospital, Teynampet, India.

4 Department of Physiology, SRMC and RI, Porur, Chennai, India.

Abstract

Background: In this era of developing targeted therapies and immunotherapies as a treatment for renal cell carcinoma
(RCC), Programmed death ligand 1 (PDL1) as a novel biomarker for RCC is analysed in our study. About 90% of all
renal cancers are Renal Cell Carcinoma. Most cases are diagnosed incidentally. 17% of cases are advanced at the time
of diagnosis. PDL1 being a trans-membrane cell surface protein is expressed on the tumor cells and is found to have a
chief role to inhibit the T cell immune response. It is essential to improve the host immunity by targeting the PD1/PDL1
pathway, thereby destroying the tumor progression. Aim: The aim of this study was to evaluate the expression of PDL1
in tumor cells and adjacent normal tissue among the renal cell carcinoma patients and assess the relation between the
PDL1 expression and the tumor characters. Methods: This is a retrospective study. Ethical clearance was obtained
from the institution. 150 histopathologically proven RCC cases were chosen. Immunohistochemistry using a PD-L1
rabbit monoclonal antibody was performed on paraffin embedded formalin fixed tissue blocks. Q scoring was done to
calculate the expression of PDL1. Statistical analysis: Chi square test was done to assess the comparison between the
PDL1 expression in tumor cells and their characteristic features like histology, grade and stage. SPSS (version 20.0)
was used for analysis. P value <0.05 was considered significant. It also explains the heterogenous nature of PDL1 as it
expressed more in the aggressive pathologic characters like high grade. Results: Positive PD-L1 expression was seen in
44% of tumors. Significant association was observed between high WWHO ISUP grading and positive PDL1 expression
(p=0.028). It was expressed in 75% of the sarcomatous type of RCC and 46.8% of clear cell RCCs. Conclusion: Our
study suggests that blocking PD1/PDL1 pathway may become an effective mode of treatment in cancer immunotherapy
especially for Renal Cell Carcinomas. Our findings confirmed the significant association between expression of PDL1
and the high graded tumors which proves it to be an important prognostic factor.

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