The CEACAM-family are glycoproteins belonging to the immunoglobulin superfamily and are expressed on the surface of various cell types, including epithelial, endothelial, and immune cells.. They play important roles in cell adhesion, cell signaling, immune responses, and inflammation. Some CEACAMs are also known to be overexpressed in certain cancers, such as colorectal, breast, and lung cancer. Because of this, they are being studied as potential biomarkers for cancer diagnosis and prognosis. CEACAM1, CEACAM5 (also known as CEA), and CEACAM6 are among the most well-known members of the family. These proteins can interact both with themselves (homophilic binding) and with other CEACAMs (heterophilic binding).

CEACAM are also expressed on various immune cells, including neutrophils, lymphocytes, and monocytes and play therfore important roles in immune regulation. CEACAM1, in particular, has been shown to act as an inhibitory receptor, helping to modulate T cell activation and prevent overactive immune responses. Some CEACAMs can transmit both activating and inhibitory signals depending on the context and binding partners.

Several pathogens, such as Neisseria, Haemophilus influenzae and H. pylori, exploit CEACAMs to attach to and evade immune responses. This makes CEACAMs not only key players in host defense, but also potential targets for immune evasion by microbes.

Dysregulation of CEACAM function has been linked to autoimmune diseases and chronic inflammation. Additionally, CEACAMs are being investigated as targets for immunotherapy, particularly in cancer, where they may help tumors escape immune surveillance. Overall, CEACAMs are emerging as important regulators.