FBXW2 and lung carcinoma: To evaluate whether increased nuclear β-catenin is transcriptionally active, we used paired TOP-Flash (which is subjected to T-cell factor/β-catenin transactivation) and FOP-Flash control luciferase reporters and found that β-catenin transactivation activity was increased upon FBXW2 knockdown, but reduced upon FBXW2 overexpression in multiple lines of lung cancer cells (Fig. 2e).