For example, XAV939 can inhibit β-catenin signaling and thus attenuate CSC progression by interacting with the terminal anchor polymerase-binding domain (TBD) in Axin [40], which can abrogate CSC-mediated chemoresistance in head and neck squamous cell carcinoma (HNSCC) and colon cancer cells [41, 42]. Here, AXIN1 is linked to head and neck squamous cell carcinoma.