Next, to prove the tumor origin of DAPI−/CD45−/EpCAM-negative/CD24−/CD44+/uPAR/int β1 cells as putative CTCs, we performed transcriptome analysis of 83 breast cancer candidate genes present in human breast cancer real-time PCR (RT2-PCR) profiler arrays (Qiagen). This evidence concerns the gene CD44 and breast cancer.