A7-associated glycoprotein antigen (A7 antigen)

The A7-associated glycoprotein antigen is a 45 kDa cell-surface molecule that serves as a highly specific marker for colorectal and pancreatic cancers. It was originally identified through the murine monoclonal antibody A7, which binds to a unique glycopeptide epitope on the surface of malignant cells but is largely absent from normal adult tissues. This high specificity has made it a primary candidate for targeted chemotherapy, where the A7 antibody is used as a carrier for cytotoxic drugs like Neocarzinostatin and Mitomycin C to increase local efficacy and reduce systemic toxicity. Beyond its role in oncology, the A7 antigen has been identified as the Insulin Receptor-related Receptor (IRR) in the context of bone biology. In this capacity, it is expressed on osteoblasts and osteocytes, acting as an alkali sensor that regulates the recruitment of osteoclasts and the initiation of bone calcification. Consequently, the A7 antigen represents a dual-interest target for both cancer-directed drug delivery and the study of bone remodeling and metabolic bone diseases.

Other names

A7 tumor-associated antigenAntigen recognized by monoclonal antibody A7Osteoblast lineage-specific cell-surface antigen A7Insulin receptor-related receptor (IRR)

Targeted drug delivery via antibody-drug conjugation; antibody-directed enzyme prodrug therapy (ADEPT); contrast enhancement for diagnostic imaging; neutralization of receptor signaling in bone remodeling.