ERBB4 and Familial prostate cancer: The EGFR family of receptor tyrosine kinases, consisting of four members (ErbB-1/HER1, ErbB-2/HER2, ErbB-3/HER3, and ErbB-4/HER4), plays crucial roles in cell growth, differentiation, and tumor migration regulation.71 The first discovered ErbB receptor is EGFR for which was first described the relationship between overexpression and cancer development.72 Alterations in ErbB family members were found to be correlated with the progression of numerous cancers such as ovarian, esophageal, laryngeal, breast, lung, prostate cancer, and melanoma.73–79