Chromosome Microdissection Identifies Cryptic Sites of DNA Sequence Amplification in Human Ovarian Carcinoma

DNA sequence amplification contributes to the multistep process of carcinogenesis, and overexpression of amplified genes has been shown to contribute to the malignant phenotype. Cytogenetic analyses of human tumor cells, including ovarian malignancies, frequently show cytologicai evidence of DNA amplification in the form of double minutes and homogeneously staining regions. In this report, we have combined the techniques of chromosome microdissection and fluorescence in situ hybridization (P. S. Meltzer et aL, Nat Genet, 1: 24-28, 1992) to identify the composition and chromosomal origin of seven homogeneously staining regions from seven cases of ovarian cancer. Twelve specific chromosome band regions were identified as amplified including llq, 12p, 16p, 19p, and 19q. These results provide important insights into the organization of amplified sequences within ovarian malignancies and add further to our recognition of regions likely to harbor genes important to the development or progression of ovarian cancer.