Correlation of pd-l1 staining in tumor cells and tumor infiltrate between primary tumors and matched metastasis in advanced colorectal cancer patients

Introduction: To date, published studies have failed to demonstrate a predictive role of PD-1/PD-L1 immunostainings in metastatic (met) colorectal cancer (mCRC) patients (pts) submitted to immunotherapy. However, in mCRC as well as in other solid tumors, there is great interest on the description of concordance of PD-L1 expression between different sites of disease in the same patient. As data on receptor positivity are more easily obtained from...