Aberrations of the p53 gene in 26 surgical specimens of human epitheli
al ovarian carcinomas were examined by single-strand conformation poly
morphism (SSCP) analysis of polymerase chain reaction (PCR) products.
Seven (27%) of the tumors demonstrated a SSCP band shift in exons 4 to
9 of the gene, including 5 in the region encompassing exons 5 and 6,
1 in exon 7, and 1 in the region encompassing exons 8 and 9. Mutations
were clustered in exon 5 in highly conserved regions of the p53 gene.
All of the abnormal DNA fragments have been further characterized by
direct DNA sequencing. These include five missense mutations (five tra
nsitions), a one-base-pair deletion introducing, by frameshift, a stop
codon further downstream, and a two-base-pair insertion introducing a
stop codon downstream by frameshift. Most mutations were base substit
utions, and were clustered in exon 5 (71%), especially codons 175 and
179. The aberrations of the p53 gene were only found in tumors of FIGO
stages III and IV. Histologic grading was also reviewed with respect
to p53 aberrations. The aberrations were absent in well-differentiated
carcinomas. The more undifferentiated the primary tumor, the more fre
quent p53 mutation (P < 0.05). Our results indicated that the aberrati
ons of the p53 gene were common in epithelial ovarian cancers and p53
aberration may occur late during ovarian cancer evolution. (C) 1995 Ac
ademic Press, Inc.