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