The members of this family, EGFR, c-erbB-2, c-erbB-3 and c-erbB-4 (also known as HER-1, HER-2, HER-3 and HER-4, respectively) are normally located on cell membranes and consist of an extracellular ligand-binding domain and an intracellular domain with tyrosine kinase activity [8].The EGF signalling pathway has been studied in human cancer patients with particular attention paid to EGFR, HER-2 and their activating ligands as the deregulation of these has been shown to play an important role in tumour initiation, progression and metastasis [7], [8]. The gene discussed is ERBB2; the disease is neoplasm.