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. Author manuscript; available in PMC: 2010 Feb 11.
Published in final edited form as: Nat Med. 2007 Jul 31;14(9):985–990. doi: 10.1038/nm.1789

Figure 1. Measurement of ctDNA.

Figure 1

The left side of the schematic depicts conventional Sanger sequencing of DNA derived from the subject’s tumor, representing the first step of the analysis. The approach for quantifying tumor-derived DNA in plasma samples is shown on the right. Real-time PCR is used to measure the total number of DNA fragments in the plasma, whereas BEAMing measures the ratio of mutant to wild-type fragments labeled with the fluorescent probes Cy5 and Cy3, respectively.