CSNK1A1 and breast cancer: More recently, pyrvinium was shown to bind and activate CK1α, a member of the β-catenin destruction complex, and thereby suppresses Wnt/β-catenin signaling [33], Consistent with this, our findings demonstrate that pyrvinium or 4-OHT-pyrvinium treatment selectively reduce the viability of ER+ breast cancer cells with INPP4B overexpression.