CTNNB1 and metastatic neoplasm: CTNNB1, a key component of the Wnt signaling pathway, is characterized above (Figure 2).[15] CTNNB1 exon 3 mutations, such as T41A, are considered to be activating the Wnt pathway.[22] At the time of referral to the CCTT the patient had metastatic disease to the liver and decided to pursue therapeutic options outside of MD Anderson.