CEACAM5 and breast cancer: When the cell tissue becomes cancerous, CEA differentiates from endoderm cells into cell membrane structural proteins, forms in the cytoplasm, and is secreted into the body through the cell membrane.27,28 CEA expression is relatively stable and represents the normal operation of blood vessels and can also be used as an indicator of endocrine function.29 However, when breast cell disease occurs, CEA will increase abnormally, and overexpression will also induce the production of excessive protein tyrosine kinase, suggesting CEA expression level is closely related to the process of LNM in BC.