A challenge in analyzing these relationships is the high degree of homology between CEACAM1 and other human CEACAM family members such as CEACAM3, CEACAM5, CEACAM6, and CEACAM8 in their IgV-like, membrane-distal N-domain7,17 that are also expressed on immune and non-immune cells in the tumor microenvironment (TME)13,16. The gene discussed is CEACAM1; the disease is neoplasm.