However, other members of the WNT signaling pathway like the tumor suppressor genes APC, Axin1, or Axin2/Conductin were shown to harbor mutations as alternative genetic alterations [9, 19, 22, 23], while only CTNNB1 and APC mutations were found in a substantial fraction of WNT-MBs [33, 35, 38, 43, 44]. Here, CTNNB1 is linked to neoplasm.