Ji et al. [63] discovered that in osteosarcoma cells U2OS, the SIAH1 protein interacts with the VxP motif within the GSK3-binding region of Axin, promoting the ubiquitination–proteasomal degradation pathway of Axin and thereby enhancing the stability of WNT-induced β-catenin. The gene discussed is AXIN1; the disease is osteosarcoma.