Today, we know that EpCAM is present as a heart-shaped cis-dimer at the cell surface2, and that it has a broader but nevertheless sharply restricted expression pattern in undifferentiated pluripotent embryonic stem cells (ESC)3–5, hepatic, pancreatic epithelial and other endodermal progenitor cells6–8, epithelium9, carcinoma and cancer stem cells10,11. This evidence concerns the gene EPCAM and cancer.