Investigation of PD-L1 Biomarker Testing Methods for PD-1 Axis Inhibition in Non-squamous Non-small Cell Lung Cancer

This study compares multiple methods of biomarker testing for treatment of NSCLCs with PD1-axis inhibitors. Tissue microarrays of matched primary and metastatic NSCLCs were used to compare four different PD-1 ligand (PD-L1) IHC techniques, as well as RNA ISH. Additional cases with whole genome and transcriptome data were assessed for molecular correlates of PD-L1 overexpression. Eighty cases were included in the IHC study. Multiple IHC methodologies showed a high rate of agreement (Kappa = 0.67). When calibrated to RNA expression, agreement improved significantly (Kappa = 0.90, p=0.0049). PD-L1 status of primary and metastatic tumors was discordant in 17 (22%) cases. This study suggests that different IHC methodologies for PD-L1 assessment provide slightly different results. There is significant discordance between the PD-L1 status of primary tumors and lymph node metastases. RNA ISH may be a useful adjunct to complement PD-L1 IHC testing.

Source: Journal of Histochemistry and Cytochemistry - September 24, 2016 Category: Biochemistry Authors: Sheffield, B. S., Fulton, R., Kalloger, S. E., Milne, K., Geller, G., Jones, M., Jacquemont, C., Zachara, S., Zhao, E., Pleasance, E., Laskin, J., Jones, S. J. M., Marra, M. A., Yip, S., Nelson, B. H., Gown, A. M., Ho, C., Ionescu, D. N. Tags: Articles Source Type: research