FcγRIII & HER2

HER2 is a protein encoded by the ERBB2 gene, and it is a member of the epidermal growth factor receptor (EGFR) family. It plays a crucial role in cell growth and differentiation. Overexpression or amplification of the HER2 gene is associated with several aggressive forms of cancer, most notably breast cancer. This overexpression leads to increased cell proliferation and tumor growth, making HER2 a significant target for cancer diagnostics and therapeutics. Monoclonal antibodies and small molecule inhibitors that target HER2 have significantly improved outcomes for patients with HER2-positive cancers.

This gene encodes a receptor for the Fc portion of immunoglobulin G, and it is involved in the removal of antigen-antibody complexes from the circulation, as well as other other antibody-dependent responses. This gene (FCGR3A) is highly similar to another nearby gene (FCGR3B) located on chromosome 1. The receptor encoded by this gene is expressed on natural killer (NK) cells as an integral membrane glycoprotein anchored through a transmembrane peptide, whereas FCGR3B is expressed on polymorphonuclear neutrophils (PMN) where the receptor is anchored through a phosphatidylinositol (PI) linkage. Mutations in this gene have been linked to susceptibility to recurrent viral infections, susceptibility to systemic lupus erythematosus, and alloimmune neonatal neutropenia. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.