CEA

Introduction

Carcinoembryonic Antigen (Colorectal Cancer, CEA), also known as Carcinoembryonic Antigen-Related Cell Adhesion Molecule 5 (CEACAM5), is a tumor-associated antigen extracted from colorectal cancer and embryonic tissues, with a molecular weight of 180~200 kDa. CEA belongs to the immunoglobulin superfamily and is a member of the cell adhesion molecule family. In the normal mucosa of the intestinal tract, trace amounts of CEA are synthesized in goblet cells and columnar cells, existing in the form of a glycoprotein coat on the cell or microvilli surface. After shedding, it is excreted with feces and does not enter the capillaries. However, in the case of dysplasia or malignancy in the colonic mucosal epithelium, there is a significant increase in both intracellular and extracellular CEA, reaching several times or even tens of times the normal levels.

Clinical Significance

As a broad-spectrum tumor marker, CEA is currently widely used in the detection of gastrointestinal cancers, especially colorectal cancer. Colorectal cancer is a common malignant tumor of the digestive system in China, and early non-invasive diagnosis is challenging. CEA has a sensitivity and specificity of 36% and 87%, respectively, in the diagnosis of colorectal cancer. It plays a crucial role in the treatment, prognostic assessment, monitoring of recurrence, and evaluation of treatment response.