EpCAM

EpCAM (Epithelial Cell Adhesion Molecule) is a transmembrane glycoprotein that plays a crucial role in cell adhesion and signaling. It is encoded by the EpCAM gene, also known as TACSTD1 (Tumor-Associated Calcium Signal Transducer 1). EpCAM is primarily expressed in epithelial cells and is involved in various physiological and pathological processes.

Structure

EpCAM is a type I transmembrane protein consisting of an extracellular domain, a transmembrane domain, and a cytoplasmic domain. The extracellular domain contains two epidermal growth factor (EGF)-like repeats and a thyroglobulin type-1 domain. These domains are responsible for mediating cell-cell adhesion and binding to other proteins.

Function

EpCAM functions as a homophilic cell adhesion molecule, meaning it binds to other EpCAM molecules on adjacent cells. This interaction promotes cell-cell adhesion and helps maintain the integrity of epithelial tissues. EpCAM also plays a role in cell signaling pathways, including the Wnt/β-catenin pathway, which regulates cell proliferation and differentiation.

In addition to its adhesive and signaling functions, EpCAM is involved in the regulation of cell migration and invasion. It has been shown to promote the epithelial-mesenchymal transition (EMT), a process in which epithelial cells lose their cell-cell adhesion and acquire a more migratory and invasive phenotype. EpCAM expression has been associated with increased metastasis and poor prognosis in various types of cancer.

Clinical Significance

Due to its involvement in cancer progression and metastasis, EpCAM has gained significant attention as a potential therapeutic target. Antibodies targeting EpCAM, such as cetuximab and catumaxomab, have been developed for the treatment of certain types of cancer. These antibodies can inhibit EpCAM-mediated cell adhesion and signaling, leading to reduced tumor growth and metastasis.

EpCAM has also been explored as a diagnostic and prognostic marker in cancer. Its overexpression has been observed in various types of epithelial tumors, including breast, colon, lung, and ovarian cancers. Detection of EpCAM expression in tumor tissues or circulating tumor cells can provide valuable information for cancer diagnosis, staging, and monitoring of treatment response.

References

1. Maetzel D, et al. (2009). "Nuclear signalling by tumour-associated antigen EpCAM". Nat Cell Biol. 11(2):162-71. doi: 10.1038/ncb1824. 2. Trzpis M, et al. (2007). "EpCAM in morphogenesis". Front Biosci. 12: 442-50. doi: 10.2741/2077. 3. Went P, et al. (2004). "Expression of EpCAM (CD326) in non-small cell lung cancer, colon cancer, and ovarian cancer. Analysis of 5,000 tissue samples using tissue microarray". Appl Immunohistochem Mol Morphol. 12(4): 267-70. doi: 10.1097/00129039-200412000-00001.