ERBB2 and prostate cancer: For example, research suggests that human epidermal growth factor receptor 2 (HER2) and epidermal growth factor receptor (EGFR) are upregulated in response to ADT; [66, 67] in addition, a recent study demonstrated that EGFR promotes the survival of prostatic tumor infiltrating cells and circulating tumor cells that metastasize to bone, and that HER2 supports the growth of prostate cancer cells once they are established at the site of metastasis [68].