DKK1 and neoplasm: While Dkk-1 can serve as a tumour suppressor in some cases by inhibition of cWnt [56] the complications of Dkk-1 signalling make its specific effect on tumour physiology unpredictable and there are several reported examples of Dkk-1 serving a pro-tumorigenic role through enhancement of growth and/or survival [15, 54, 57, 58], migratory [59], and metastatic [21, 54] characteristics.