CTNNB1 and adenoma: Moreover, upregulation of BCL9-2 in tumors and adenoma was unchanged by Pygo2 ablation, indicating that Bcl9-2 expression is not activated by Pygo2. In fact, BCL9-2 expression is apparently suppressed by active Wnt signaling as we found loss of BCL9-2 expression in the hyperproliferative regions in both Apc and Ctnnb1 mutant models.