ERBB2 and breast cancer: The molecular constituents of cell–cell communication pathways have been identified thanks to extensive genetic analysis research [44]; and the identification of genes associated with a specific tissue has been useful for highlighting their biological function, providing context for disease states, like breast cancer and subtype as BRCA-Basal, BRCA-Her2, BRCA-Lum-A, and BRCA-Lum-B.