ERBB4 and cancer: The EGF receptor (EGFR) (or HER) proto-oncogene family consists of four transmembrane tyrosine kinase receptors (i.e., EGFR, ErbB2, ErbB3, and ErbB4) that play a role in cancer pathogenesis and has been described as key therapeutic target in many types of cancer, including ovarian cancer (63).