EPCAM & CD28

EPCAM encodes a cell surface glycoprotein that is involved in maintaining cell-cell adhesion, particularly in epithelial tissues. It plays an important role in the regulation of cell migration, proliferation, and differentiation. EPCAM is widely expressed in various epithelial tissues and is a crucial marker for certain types of cancer, particularly epithelial cancers like colorectal carcinoma. Mutations in EPCAM can lead to congenital defects, such as congenital tufting enteropathy, a rare disorder that causes severe gastrointestinal symptoms. EPCAM is also involved in stem cell biology and cancer stem cell regulation.

CD28 is a co-stimulatory receptor found on T cells that plays a key role in T-cell activation and survival. It is a transmembrane protein expressed on naïve and activated T cells, binding to B7-1 (CD80) and B7-2 (CD86) on antigen-presenting cells (APCs). This interaction provides the necessary secondary signal for full T-cell activation, alongside T-cell receptor (TCR) engagement with antigen-presenting major histocompatibility complex (MHC). CD28 signaling promotes cytokine production, T-cell proliferation, and survival. In the absence of CD28 signaling, T cells may become anergic (non-responsive). Because of its role in immune regulation, CD28 is a target for therapeutic interventions in autoimmune diseases, transplantation, and cancer immunotherapy.