Tumor-specific p53 sequences in blood and peritoneal fluid of women with epithelial ovarian cancer

Objective Free tumor DNA in body fluids may be an important biomarker. We tested whether tumor-specific mutated p53 DNA can be detected in blood and peritoneal fluid from women with epithelial ovarian cancer. Study design Sequencing of tumor DNA identified somatic p53 mutations. Free DNA from matched blood or peritoneal fluid was evaluated for the tumor-specific p53 mutation using a ligase detection reaction. Results Sixty-nine of 137 tumors (50%) had p53 mutations. Plasma or serum from 21 (30%) of the 69 informative cases contained the tumor-specific p53 mutation. Circulating tumor was an independent predictor of decreased survival in multivariate analysis (P = .02). We detected tumor DNA in peritoneal fluid in 28 of 30 (93%) cases, including all 6 cases with negative cytology. Conclusion One third of women with ovarian cancer have circulating tumor DNA and an associated reduced survival. Free tumor DNA can be detected in the majority of peritoneal fluid samples.