ERBB2 and cancer: The amplification of the HER-2 geneand overexpression of the HER-2 protein is frequently observed (10–40%) in humanbreast cancer patients [23] and has been suggested to associate with tumoraggressiveness, prognosis, and responsiveness to hormonal and cytotoxic agents.These observations suggest that HER-2 is an appropriate target fortumor-specific therapies, some of which are listed as follows.