PD-L1 Assay Concordance in Metastatic Renal Cell Carcinoma and Metastatic Urothelial Carcinoma - Expert Commentary

Understanding the concordance rates for different biomarkers assays is critical for assessing their performance. A new study published by Brown et al. in Clinical Genitourinary Cancer evaluated the concordance of the programmed death-ligand 1 (PD-L1) expression assays in patients with metastatic renal cell carcinoma (mRCC) and metastatic urothelial carcinoma (mUC). 

The authors compared the Dako 28-8 and Ventana SP142 assays using tissue samples from 32 patients with mRCC. In the mRCC group, the concordance rate was 91% (29 out of 32). The Dako 22C3 and Ventana SP263 assays were also compared in tissue samples from 18 patients with mUC. In this group, the concordance rate was 94.4% (17 out of 18).

The study concluded that these PD-L1 assays were generally concordant and had similar performance characteristics suggesting that they can be used interchangeably. While these standardized tests are designed to yield binary positive and negative results, it is crucial to understand that these results rely on crossing a certain threshold, whereas the expression of a given protein, such as PD-L1, is a continuous variable.


Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine 
References:

  1. Brown LC, Zhu J, Labriola MK, Wu Y, Cheris S, Liu X, Perkinson K, Su Z, McCall S, Huang J, Foo WC, Gupta RT, Armstrong AJ, George DJ, Harrison MR, Zhang T. “PD-L1 Assay Concordance in Metastatic Renal Cell Carcinoma and Metastatic Urothelial Carcinoma.” Clin Genitourin Cancer. 2020 Apr 10:S1558-7673(20)30092-6. doi: 10.1016/j.clgc.2020.03.020. Online ahead of print. PMID: 32482566
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