One such protein is the epidermal growth factor receptor (EGFR), a member of the erbB receptor tyrosine kinase family also comprising erbB2, erbB3 and erbB4 and which has been shown to play a central role in driving both de novo and acquired anti-hormone-resistant growth and invasion in breast cancer [22-25]. The gene discussed is EGFR; the disease is breast carcinoma.