Figure 1: General workflow of droplet digital PCR in amplification analysis of archival cancer samples. DNA is extracted from an archival cancer sample. An example of a formalin-fixed paraffin block of gastric adencarcinoma with an accompanying stained section is shown. After DNA extraction, droplet PCR is conducted with a specific set of PCR primers and fluorescent probe. Post-PCR emulsion droplets are streamed single-file into a capillary that leads past a two-color detector; where the positive droplets for the target and reference genes are counted for copy number quantitation with two different dyes such as 6-FAM and VIC. One dye is specific to the control loci and the other to the loci being measured.