The signature was then validated in female healthy donors and in patients with stage I to IV breast cancer upon microfluidics-based enrichment and EpCAM-dependent capture of CTCs by using the herringbone CTC-iChip [130], and after optimizing digital droplet PCR detection signals by subtracting background signals detected in a preliminary cohort of 30 female healthy donors. This evidence concerns the gene EPCAM and breast carcinoma.