Deletion of tp53 exon-1 in human epithelial ovarian-cancer.

In ovarian cancer, allelic loss within 17p 13.1-13.3, which contains the tumor suppressor TP53, occurs with a frequency of 66%, and mutations within conserved TP53 exons are reported in approximately 50% of cases. We examined DNA from 26 Stage III/IV ovarian carcinomas and 7 non-malignant ovaries by Southern blot hybridization and PCR for gene rearrangement or deletion within the,TP53 locus. Deletion specifically involving loss of the transcription-regulatory exon 1/intron 1 region on at least one allele was detected in 24/26 (92%) cases, and 0/7 noncancerous ovaries. Immunocytochemical analysis confirmed absence of expression of mutant p53 protein in those tumors where loss of the exon 1 region involved both alleles.