Genetic alterations of serous borderline tumors of the ovary compared to stage I serous ovarian carcinomas.

Borderline tumors of the ovary comprise 10-20% of all epithelial ovarian tumors, and are placed between clearly benign and obviously malignant ovarian tumors. The issue of whether borderline tumors are precursors of invasive carcinoma or distinct clinical entities, however, is still the subject of discussion. To increase our understanding in relation to this issue, the aim of our study was to analyze both serous borderline and invasive ovarian tumors, and to investigate early carcinogenesis in serous ovarian tumors. Using comparative genomic hybridization, we compared cytogenetic changes in borderline ovarian tumors and stage I invasive tumors. The average number of genetic alterations differed significantly between the borderline and the invasive tumors (1.9 and 9.2, respectively). The most common genetic alterations among the borderline tumors were loss of chromosome 17, 20q, and 18p, and gain of 12p13 approximately q23. These changes were also found among the invasive tumors in a similar percentage. In conclusion, we found four distinct cytogenetic alterations that might be early events in serous ovarian tumors, and that might also characterize a subgroup of borderline ovarian tumors that may have the potential to progress and develop malignancy.