DKK1 and cancer: There are cancer treatments (experimental at this time) that inhibit Wnt signaling and may be a possibility in the future, particularly porcupine inhibitors which interfere with Wnt ligands [3,11]. In vitro studies also show a potential treatment with a signaling protein Dickkopf-1 (Dkk-1), which has been shown to be involved in the normal inhibition of Wnt signaling [5].