Profiling serum HER-2/NEU in prostate cancer

One of the four transmembrane receptors that belong to the erB family, is the HER2/neu oncoprotein. It forms heterodimers by binding to specific ligands, enhancing cell signaling and assisting in cell growth and differentiation. A variety of human epithelial tumors are characterised by an overexpression and gene amplification of the HER2/neu oncoprotein. This is the case of breast tumors, in which the receptor's overexpression and its gene have been studied extensively and its overexpression has been associated with unfavorable prognosis. In addition, HER2/neu plays a major role in understanding the oncogenesis of prostate adenocarcinoma. For this reason, clarifying the HER2/neu expression is particularly important in androgen independent prostate cancer (PCa), due to the increasing interest in using anti-HER2 targeted therapies for advanced disease treatment. On the other hand, the overexpression of HER2/neu has been reported to release soluble extracellular domain (ECD) in the serum of PCa patients. For this reason, the present review focuses only on studies referring to Serum HER2/neu levels in PCa patients. Serum levels of HER2/neu generally increase with advanced disease state and higher levels have been associated with recurrent or metastatic PCa and a clinically worse outcome. Therefore, it may be concluded that since there is a correlation between increased HER2/neu levels and a poor prognosis in prostate adenocarcinoma, serum HER2/neu could be used in clinical practice and follow up of patients with advanced PCa.