MMP9 and gastric cancer: The activity of MMP9 in the tumor microenvironment has been investigated in several cancer models.5 6 Preclinical studies have suggested that MMP9 inhibition can reverse immune suppression, promote T-cell infiltration, and potentiate checkpoint blockade.7 8 In patients with gastric cancer, elevated expression levels of MMP9 protein and mRNA are associated with reduced overall survival (OS).9–11 Andecaliximab is a recombinant chimeric IgG4 monoclonal antibody that demonstrates high affinity and selectivity for MMP9.