The over-expression of Wnt5a in these two cell lines activated protein kinase A (PKA), which phosphorylates and inactivates GSK3β, leading to stabilization and activation of β-catenin, which in turn induces the expression of ATP-binding cassette sub-family B member (ABCB1), a key protein that is responsible for pumping therapeutic drugs out of cancer cells, leading to MDR. Here, WNT5A is linked to cancer.