Universitats Kinderspital Zurich 1 article published in JoVE Cancer Research Detection and Monitoring of Tumor Associated Circulating DNA in Patient Biofluids Erin R. Bonner1,2, Karim Saoud1, Sulgi Lee1,2, Eshini Panditharatna3, Madhuri Kambhampati1, Sabine Mueller4,5, Javad Nazarian1,2,5 1 Here, we present a protocol to detect tumor somatic mutations in circulating DNA present in patient biological fluids (biofluids). Our droplet digital polymerase chain reaction (dPCR)-based method enables quantification of the tumor mutation allelic frequency (MAF), facilitating a minimally invasive complement to diagnosis and temporal monitoring of tumor response.