The former represent a hyper-mutated and highly inflamed form of colorectal cancers (MSIhi CRC) (49) transfected to stably express human CEA (MC38-hCEA), the latter an aggressive form of murine gastric cancer with immune desert phenotype, which is poorly responsive to cancer immunotherapy treatment (Steinhoff N et al., in preparation). The gene discussed is CEACAM5; the disease is gastric cancer.