ASCO 2017: Differential expression of c-Met between primary and metastatic sites in clear-cell renal cell carcinoma and its association with PD-L1 expression

Chicago, IL ( Preclinical models show that c-Met promotes survival of renal cancer cells through the regulation of programmed death-ligand 1 (PD-L1). Due to the lack of data on the relationship between c-Met and PD-L1 in human clear cell renal cell carcinoma (ccRCC), the authors presented a study comparing c-Met expression between primary and metastatic sites in ccRCC tissues and evaluated the association with PD-L1 expression. 

Paired primary and metastatic samples from 45 ccRCC patients were included in this analysis. Only areas with predominant and highest Fuhrman nuclear grade (FNG) were selected. c-Met expression was evaluated by IHC using an anti-Met monoclonal antibody (MET4 Ab, VARI). PD-L1 expression was assessed by IHC. c-Met expression (average c-Met CS) between paired primary and metastatic samples were compared. Associations of c-Met expression with PD-L1 expression (+/-) and other clinical features were assessed as well. 

The final cohort included 45 primary ccRCCs and 54 corresponding metastases. c-Met expression was higher in metastatic sites compared to primary (c-Met CS: 55 vs. 28, p=0.0003) and was numerically-greater in PD-L1+ vs. PD-L1- tumors. Higher c-Met expression was associated with higher FNG and T-stage in both primary and metastatic sites, as shown in the table below. 

In summary, higher c-Met expression was demonstrated in metastases compared to paired primary tumors in our cohort of ccRCC. Although the observation that higher c-Met expression was shown in PD-L1+ tumors, it still requires further investigation.

Presented By: Aly-Khan A. Lalani, Dana-Farber Cancer Institute, Boston, MA

Written By: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre
Twitter: @GoldbergHanan

at the 2017 ASCO Annual Meeting - June 2 - 6, 2017 - Chicago, Illinois, USA