PDCD1 and gastric cancer: A recent meta-analysis of randomized clinical trials evaluated the role of MSI as a positive predictive factor for PD-1 immunotherapy as first- or second-line regimens in patients with advanced GC.63 The study included data from KEYNOTE-061, CHECKMATE-649, JAVELIN Gastric 100, and KEYNOTE-062,29,30,32,64 and provided evidence of improved survival and response in advanced patients with GC with MSI-high tumors who received anti-PD-1 blockade, with significantly greater OS compared with patients with MSS tumors.