Targeting the epidermal growth factor receptor in epithelial ovarian cancer: current knowledge and future challenges

The epidermal growth factor receptor is overexpressed in up to 60% of ovarian epithelial malignancies. EGFR regulates complex cellular events due to the large number of ligands, dimerization partners, and diverse signaling pathways engaged. In ovarian cancer, EGFR activation is associated with increased malignant tumor phenotype and poorer patient outcome. However, unlike some other EGFR-positive solid tumors, treatment of ovarian tumors with anti-EGFR agents has induced minimal response. While the amount of information regarding EGFR-mediated signaling is considerable, current data provides little insight for the lack of efficacy of anti-EGFR agents in ovarian cancer. More comprehensive, systematic, and well-defined approaches are needed to dissect the roles that EGFR plays in the complex signaling processes in ovarian cancer as well as to identify biomarkers that can accurately predict sensitivity toward EGFR-targeted therapeutic agents. This new knowledge could facilitate the development of rational combinatorial therapies to sensitize tumor cells toward EGFR-targeted therapies.

The emerging role of epidermal growth factor receptor inhibitors in ovarian cancer

Epidermal growth factor receptor (EGFR) inhibitors are a new biologically targeted therapy, which may offer new hope in the treatment of patients with advanced or recurrent ovarian cancers. In this review, we summarize and discuss the results of research to date on EGFR inhibitors with particular emphasis on ovarian cancer. We reviewed data identified by searches of MEDLINE, PubMed, and abstracts from the proceedings of the American Society of Clinical Oncology meetings from 1998 to 2006, with the search terms “Ovarian Cancer,” “EGFR,” “gefitinib, ZD1839, Iressa,” “erlotinib, OSI-774, Tarceva,” “CI-1033,” “ GW 572016, lapatinib,” “PKI-166,” “EKB 569,” “anti-EGFR antibodies,” “trastuzumab, Herceptin,” “cetuximab, Erbitux, IMC-C225,” “matuzumab, EMD 72000,” “panitumamab, ABX-EGF,” “pertuzumab,” and “vandetanib, rINN, Zactima, ZD6474.” Phase II trials of both small molecule inhibitors of EGFR- and antibody-based inhibitors are currently ongoing in ovarian cancer and emerging data suggest that their activity in unselected women with advanced or recurrent ovarian cancer is modest, when utilized as a single agent. It is possible that these agents will be highly effective in smaller subsets of patients whose tumors are dependent on EGFR signaling, perhaps through activating mutations in EGFR or its downstream pathway. Targeted therapy with EGFR inhibitors is an untapped potential resource in the treatment of advanced or recurrent ovarian cancer. Ongoing trials will elucidate the most effective strategies to use these agents individually or in combination with traditional chemotherapeutic agents.