[Detection of extra chromosomes 12 by fluorescent in situ hybridization (FISH) in ovarian stromal tumors. Study of 12 cases and review of the literature].

Chromosomic aberrations play a major role in the initiation and the progression of benign as well as malignant tumors. In particular, trisomy 12 is frequently observed in female genitourinary tract tumors and constitutes a recurrent and often unique anomaly in stromal ovarian tumors such as fibrothecomas. Today, the genetic analysis of fresh or fixed solid tumors is enabled by the fluorescent in situ hybridization method (FISH). Using FISH and/or conventional cytogenetics, we analysed 12 ovarian stromal tumors (6 fibromas, 3 fibro thecomas and 3 thecomas). All of these tumors were benign and trisomy 12 was observed in all cases. Moreover, 3 cases presented trisomy and tetrasomy for chromosome 12 simultaneously. The high frequency of trisomy 12 in this tumor type suggests that this abnormality might be implicated in ovarian tumorigenesis.