EPCAM and breast carcinoma: Table 1 provides a summary of CTC-associated markers utilized in different cancers.22,23 The leading marker for CTCs is epithelial cell adhesion molecule (EpCAM), a “universal” epithelial marker for tumors, since the majority of tumors originate in epithelial tissues.24 Different cancer types25 express EpCAM differently, and EpCAM-based CTC detection systems are widely employed for tumors with significant EpCAM expression, like prostate and breast cancers.