EPCAM and neoplasm: Methods of CTC detection are broadly divided into nucleic-acid based approaches (PCR targeting of various epithelial mRNAs, cytokeratins (CKs) [8] and EpCAM), immunology-based (immunocytochemistry with anti-CK or -EpCAM antibodies), and epithelial immunospot (EPISPOT) assays (detecting tumor-specific proteins).