ERBB2 and neoplasm: CTC enrichment combined with a RT–PCR technology could already be used for the identification of tumor-related markers (EpCAM,MUC1, and ERBB2), EMT-associated transcripts (PI3Kα (phosphatidylinositol 3-kinase alpha), Akt-2, or Twist1), or stem cell markers such as ALDH1 (aldehyde dehydrogenase 1) (Kasimir-Bauer et al, 2012).