ERBIN (Erb-B2 Receptor Tyrosine Kinase 2 Interacting Protein) is a protein that interacts with the ErbB2 receptor, which plays a key role in cell growth and differentiation. ERBIN helps regulate signaling pathways associated with ErbB2 and other cellular functions, and it has been studied for its potential involvement in cancers where ErbB2 activity is a factor, such as breast cancer.