Strati and colleagues recently demonstrated that, in breast cancer patients (early-stage and metastatic patients), the CTC expression of epithelial markers such as CK19, EpCAM, and the bone marrow mammaglobin-1 (SCGB2A2), a specific breast cancer marker, was not correlated to the expression in CTCs of a panel including six genes indicative of the presence of CTCs (EMP2, SLC6A8, HJURP, MAL2, PPIC and CCNE2) [106,107]. The gene discussed is PPIC; the disease is breast cancer.