We found the tumor DNA detection rate in the plasma and ascites reached 100%, and the specificity of TP53 and BRCA1 in circulating tumor‐free DNA was 100% and the sensitivity 73.7% for TP53 and 75% for BRCA1, which are comparable to those of tumor tissue DNA (specificity 76.2% and sensitivity 100%). This evidence concerns the gene BRCA1 and neoplasm.