The relationship between borderline ovarian tumors and epithelial ovarian carcinoma: epidemiologic, pathologic, and molecular aspects.

Borderline ovarian tumors (BOT) are a low-grade form of ovarian malignancy with significantly less aggressive behavior than classical epithelial ovarian carcinoma (EOC). Yet, a subset of these tumors can progress and be lethal. Prognostic factors related to the development of BOT are similar to those for EOC. BOT with aneuploid DNA content have a worse prognosis; this trend is similar to that found in EOC. Patterns of loss of heterozygosity of some chromosomal abnormalities suggest that some, but not all BOT may evolve into more invasive tumors. Molecular biology has provided some clues to the pathogenesis of this entity. Increasing frequency of K-ras mutations are associated with EOC compared to BOT or benign lesions of the ovary. Platelet-derived growth factor and PDGF-alpha receptor are overexpressed in some BOT and EOC, but not in benign tumors or normal ovaries. These genetic markers suggest a closer relationship between a subset of BOT and invasive EOC. Further analysis of genetic abnormalities may delineate the relationship between BOT and EOC better, and will hopefully lead to a unifying hypothesis as to the origin of these important ovarian lesions.