Epithelial cell adhesion molecule (EpCAM) negative CTCs (Li et al., 2024) (EpCAM-CTCs) refer to CTCs that do not express EpCAM, and EpCAM- CTCs and EpCAM positive CTCs (EpCAM + CTCs) have different biological characteristics, that is to say, tumor heterogeneity. The gene discussed is EPCAM; the disease is neoplasm.