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.