RT Journal Article SR Electronic T1 HER3 Is a Determinant for Poor Prognosis in Melanoma JF Clinical Cancer Research JO Clin Cancer Res FD American Association for Cancer Research SP 5188 OP 5197 DO 10.1158/1078-0432.CCR-08-0186 VO 14 IS 16 A1 Reschke, Markus A1 Mihic-Probst, Daniela A1 van der Horst, Edward Htun A1 Knyazev, Pjotr A1 Wild, Peter J. A1 Hutterer, Markus A1 Meyer, Stefanie A1 Dummer, Reinhard A1 Moch, Holger A1 Ullrich, Axel YR 2008 UL http://clincancerres.aacrjournals.org/content/14/16/5188.abstract AB Purpose: The epidermal growth factor receptor family member HER3 is overexpressed in diverse human cancers and has been associated with poor prognosis in breast, lung, and ovarian cancer. However, the relevance of HER3 with regard to its prognostic significance and function in primary melanoma and metastases remains largely elusive. Experimental Design: HER3 protein expression was analyzed immunohistochemically using tissue microarrays of 130 primary melanoma and 87 metastases relative to established clinical variables. The possibility of an influence of HER3 on melanoma cell proliferation, migration, invasion, and chemotherapy-induced apoptosis was studied in human melanoma cell lines. Results: We show that HER3 is frequently expressed in malignant melanoma and metastases at elevated levels. High HER3 expression may serve as a prognostic marker because it correlates with cell proliferation, tumor progression, and reduced patient survival. Suppression of HER3 expression by RNA interference reduces melanoma cell proliferation, migration, and invasion in vitro. In addition, down-regulation of HER3 synergistically enhances dacarbazine-induced apoptosis. Moreover, monoclonal antibodies specific for the extracellular portion of HER3 efficiently block heregulin-induced proliferation, migration, and invasion of melanoma cell lines. Conclusion: Our results provide novel insights into the role of HER3 in melanoma and point out new possibilities for therapeutic intervention.