Indeed, EMP2 and PPIC transcripts in spiked blood samples indicated the presence of Hs579T breast cancer cells; in contrast, the analysis of the epithelial markers EpCAM, CK19 and SCGB2A2 alone would not have detected these hormone receptor and HER2-negative cells (Figure S1c). Here, SCGB2A2 is linked to breast carcinoma.