ROR1 and breast cancer: Moreover, noncanonical Wnt signaling via receptor tyrosine kinases (RTKs), such as ROR1, ROR2, and RYK, activates phosphatidylinositol-3 kinase–AKT (PI3K–AKT) signaling and is involved in numerous cancers including breast cancer, GCs, leukemia, and brain cancer [13,14].