We performed real-time-PCR (RT2-PCR) human embryonic stem cell array (Qiagen) profiling to determine the expression of 83 candidate genes in FACS-sorted EpCAM-negative, uPAR+/int β1+ and uPAR−/int β1− stem cell CTC subsets derived from clinically diagnosed breast cancer patient with or without BCBM. Here, EPCAM is linked to breast cancer.