Based on these observations, many anti-cancer treatments (e.g., all-trans retinoic acid, lysine (K)-specific demethylase 1A (KDM1A) inhibitor, polycomb complex protein BMI-1 inhibitor, antibody targeting LGR5 or the delta-like canonical Notch ligand 3 (DLL3) and drug-like inhibitors of the Wnt/β-Catenin signaling) were approved to target and eradicate CSCs in tumors with different histological origins [17]. Here, DLL3 is linked to cancer.