Fig. 1

Rational primer and probe design for ddMSP. A Graphical abstract of the detection system. B The prediction of CpG islands was performed using MethPrimer software. Cytosine bases that can be methylated are indicated in red, and the CpG island is presented in the blue area. C Sequences of the primer pairs and probes used in each assay, amplicon size, and the genome position. ccfDNA circulating cell-free DNA; ddMPCR droplet digital methylation-specific polymerase chain reaction