A monoclonal antibody directed against the Wnt signaling pathway with potential antineoplastic activity. Upon administration, vantictumab binds to certain receptors in the Wnt signaling pathway thereby preventing the activation of the Wnt signaling pathway. This may result in an inhibition of cancer stem cell (CSC) activity and a subsequent inhibition of cancer cell proliferation. The Wnt signaling pathway is dysregulated in many cancer cell types and appears to play a major role in CSC regulation and activity; CSC are tumor initiating cells that are able to self-renew and are responsible for tumor growth and resistance.