FIBROSARCOMA VERSUS CELLULAR FIBROMA OF THE OVARY - A COMPARATIVE-STUDY OF THEIR PROLIFERATIVE ACTIVITY AND CHROMOSOME-ABERRATIONS USING MIB-1 IMMUNOSTAINING, DNA FLOW-CYTOMETRY, AND FLUORESCENCE IN-SITU HYBRIDIZATION

We retrospectively analyzed the proliferative activity and the centrom etric copy number of chromosomes 8, 12, and 17 in three cases of fibro sarcoma and eight cases of cellular fibroma of the ovary using MIB-1 i mmunostaining, DNA flow cytometry, and fluorescence in situ hybridizat ion (FISH) on paraffin-embedded tissue specimens. In our study, both t he MIB-1 labeling index (LI) and the proliferative index (% of cells i n S + G2 + M phase) in fibrosarcomas were higher than those in cellula r fibromas. The FISH analysis demonstrated the sole abnormality of a g ain of trisomy 12 cells in all eight cases of cellular fibroma. Both a gain of trisomy 12 cells and a gain of tetrasomy 12 cells were observ ed in one case of fibrosarcoma. A gain of trisomy 8 cells was observed in all two fibrosarcomas in which signals were detected. By contrast, neither a gain of trisomy 8 cells nor again of tetrasomy 12 cells was observed in any of the eight cases of cellular fibroma. Chromosome 17 showed disomy in all eleven cases. In the basis of these findings, a gain of trisomy 8 cells is therefore considered to be an adequately ef fective marker to distinguish between cellular fibroma and fibrosarcom a of the ovary, and it may also be related to the proliferative activi ty of fibrosarcoma of the ovary.