Durable complete response to pembrolizumab in microsatellite stable colorectal cancer

Immunotherapy by checkpoint inhibitors, i.e., anti-programmed death-1(PD-1) or anti-programmed death-ligand 1 (PD-L1) antibodies, has gained more attention managing solid tumors. Pembrolizumab (an anti-PD-1 antibody) in metastatic colorectal cancer (CRC) was approved in 2017 by the US FDA.Pembrolizumab is not effective in microsatellite stable, mismatch-repair-proficient (MSS-pMMR) molecular phenotype, which comprises most CRC patients. In this...