DKK1 and neoplasm: Antibodies binding to DKK1 C-terminal cysteine-rich domain 2 (CRD2) restored the Wnt canonical pathway in TCF/LEF signaling and osteoblast differentiation, and binding to the DKK1 N-terminal CRD1 restored the Wnt non-canonical pathway by activating JNK phosphorylation, promoting a robust immune response, and demonstrating in vivo tumor suppressing activity.