WNT7A and osteosarcoma: For example, the atypical receptor tyrosine kinase RYK as a Wnt co-receptor interacts with Wnt3a for β-catenin stabilization in osteosarcoma cells54, and the Fzd5 receptor cooperates with Wnt7a to activate the β-catenin-mediated STF signaling in ovarian cancer cells55.