In this study, we used CD45, EpCAM, and CK7/8 to identify circulating tumor cells (CTCs, CD45-EpCAM+ CK7/8+), as well as circulating cancer cells exhibiting monoexpression of epithelial markers—CD45-EpCAM+CK7/8 and CD45-EpCAM-CK7/8+ (Epit-CCs). Here, KRT7 is linked to cancer.