Modeling the function of CEACAMs on tumor growth, the tumor microenvironment, the immune system, and inflammatory disease has been particularly challenging, with mouse models for only a tiny number, reflecting limited expression in rodents: CEACAM1 (knockout), and collectively CEABAC transgenic pooling CEACAM3, CEACAM5, and CEACAM6 [20]. The gene discussed is CEACAM5; the disease is neoplasm.