Frequent loss of heterozygosity on chromosomes Xp and 13q in human ovarian cancer.

Loss of heterozygosity (LOH) was examined at 27 loci on chromosomes 3p, 6q, 11p, 13q, 17 and X in 42 human ovarian tumors. LOH was detected in 12 of 26 (46%) and 5 of 12 (42%) informative cases at 2 chromosome 13q loci, D13S32 and D13S34 respectively. On chromosome Xp, tumor-specific allele loss was observed in 9 out of 15 informative cases (60%) at the ornithine transcarbamylase (OTC) gene locus. Examination of 12 additional Xp and 13q loci has mapped the common deletion regions to Xp21.1-->p11.4 and 13q33-->q34. The observation of significant LOH on Xp represents a strong indication of genetic changes in the X chromosome in a human malignancy. The allele losses on 13q which have been reported for other cancers suggest that chromosome 13, in addition to the retinoblastoma gene, may contain other growth-regulating gene(s) important in the development of several tumor types, including ovarian malignancies.