ROR1 and breast cancer: Nonetheless, we found that cirmtuzumab could inhibit the capacity of Wnt5a to induce tyrosine phosphorylation of cortactin in serum-starved ROR1+breast-cancer PDX, even at Wnt5a concentrations of 100 ng/ml (Fig. 2c, d), indicating that the Wnt5a-induced phosphorylation of cortactin was dependent on ROR1.