EPCAM and melanoma: However, isolation and characterization of melanoma cells from complex biological samples present significant challenges since: (i) Melanoma cells in the circulation are present at very low frequencies (averaging 1–100 cells/ml) in comparison to peripheral blood cells (107)16, and (ii) with epithelial cell adhesion molecule (EpCAM) forming the basis of most circulating tumour cells (CTCs) isolation strategies17, 18, its absence on melanoma cells and other non-epithelial cancers highlights the need for additional markers and versatile platforms that can easily incorporate different markers19.