The ErbB protein family or epidermal growth factor receptor (EGFR) family is a family of four structurally related receptor tyrosine kinases. Insufficient ErbB signaling in humans is associated with the development of neurodegenerative diseases, such as multiple sclerosis and Alzheimer's Disease. In mice loss of signaling by any member of the ErbB family results in embryonic lethality with defects in organs including the lungs, skin, heart and brain. Excessive ErbB signaling is associated with the development of a wide variety of types of solid tumor. ErbB-1 and ErbB-2 are found in many human cancers and their excessive signaling may be critical factors in the development and malignancy of these tumors. The ErbB protein family consists of 4 members * ErbB-1, also named epidermal growth factor receptor (EGFR) * ErbB-2, also named HER2 in humans and neu in rodents * ErbB-3, also named HER3 and * ErbB-4, also named HER4 The four members of the ErbB protein family are capable of forming homodimers, heterodimers, and possibly higher order oligomers upon activation by a subset of potential growth factor ligands. This pathway was inferred from Homo sapiens pathway [http://www.wikipathways.org/index.php?title=Pathway:WP673&oldid=29836 WP673(r29836)] with a 96% conversion rate. epidermal growth factor/neuregulin signaling pathway PW:0000170 Pathway Ontology cancer DOID:162 Human Disease Ontology multiple sclerosis DOID:2377 Human Disease Ontology Alzheimer's disease DOID:10652 Human Disease Ontology