In the present study, the transcript levels of a 6-gene panel (CCNE2, PPIC, MAL2, EMP2, HJURP, and SCL6A8) previously published as candidate CTC markers [11], and of epithelial cell lineage-specific (EpCAM, CK19) and breast cancer-specific (SCGB2A2) markers were assessed. Here, KRT19 is linked to breast cancer.