Computer tomography (CT), CTC images and EpCAM immunostaining of CRC tumors. EpCAM is consistently expressed in CRC primary tumors, also in patients that have no CTCs detectable by EpCAM-based CellSearch® system. Shown are: mean CTC numbers (±SEM), the actual liver/tumor volume ratio, a CTC (CellSearch® system qualifies a cell as a CTC if it has an evident nucleus by DAPI and if it is EpCAM+, cytokeratin 8/18/19+, and CD45-), (A) CT scan of a patient with a high tumor/liver ratio (≥30%) and high baseline CTCs (≥3), (B) EpCAM immunostaining with a monoclonal antibody (BerEP4) and peroxidase method of the respective CRC primary tumor, (C) CT scan of a patient with a low high tumor/liver ratio (<30%) zero baseline CTCs, and (D) EpCAM immunostaining of the respective CRC primary tumor.