Genetic analysis of benign, low-grade, and high-grade ovarian tumors.

Genetic abnormalities were assessed in 56 benign, low-, and high-grade ovarian tumors using comparative genomic hybridization (CGH) and analysis of loss of heterozygosity (LOH). In addition, 95 epithelial tumors were analyzed for microsatellite repeat instability. DNA sequence copy number abnormalities (CNAs) were not detected in the benign tumors, and more were detected in high-grade than in low-grade cancers. Almost no microsatellite repeat instability was detected in these cancers. CNAs occurring in more than 30% of the cancers included increased copy number on 3q25-26 and 8q24 and reduced copy number on 16q and 17pter-q21. Another 14 CNAs occurred in more than 20% of the cancers. Increased copy number at 3q25-26 and 20q13 was the most frequent CNA in low-grade tumors, and increased copy number at 8q24 occurred preferentially in high-grade tumors. The presence of a large number of CNAs per tumor was significantly correlated with reduced patient survival duration. Reduced copy number on 17pter-q21 was most strongly associated with accumulation of a large number of CNAs. The overall concordance between LOH and reduced copy number detected by CGH was 84%, but only 31% of the LOH was associated with reduced copy number detected using CGH.