In the case of melanoma, High-Molecular Weight-Melanoma-Associated Antigen/Melanoma-associated Chondroitin Sulfate Proteoglycan (HMW-MAA/MCSP) has been identified and can be used for CTC isolation.17 Mesenchymal tumors and tumors that have undergone epithelial to mesenchymal transition are likewise not detected by EpCAM-based assays.17 Further modifications to existing technology for isolation of CTCs from other tumor types will be needed. This evidence concerns the gene EPCAM and melanoma.