Defining new ovarian cancer factors through the molecular analysis of ovarian tumors may aid in the development of targeted therapeutics and more sensitive biomarkers for this disease. Secreted polypeptide growth factors are known to regulate gene expression and contribute to cell transformation and tumorigenesis. The role of growth factors in ovarian cancer development and progression appears to be complex and multifactorial. Transforming growth factor-ß, macrophage colonystimulating factor, and lysophosphatidic acid have all been shown to promote ovarian cancer growth, invasion, and metastasis [1–6]. Several of these growth factors are also important predictors of ovarian cancer outcome and may be biomarkers and/or therapeutic targets.

Novel and high-throughput technologies have been applied by our laboratory for the molecular dissection of the ovarian cancer cell as it exists in its native environment. We have previously demonstrated that laser capture microdissection may be combined with genomic, genetic, and proteomic applications to define genes and proteins associated with invasive ovarian cancer [7, 8]. Granulin–epithelin precursor (GEP), a newly defined yet poorly characterized growth factor, was recently discovered by our laboratory to be highly expressed in invasive epithelial ovarian cancers and differentially expressed between invasive and noninvasive, low-malignant-potential (LMP) ovarian tumors. We now review the identification and characterization of this protein to date and discuss its potential importance in ovarian cancer.