DKK1 and breast cancer: Among the potential markers, Dickoppf-1 (DKK-1) has shown interesting evidences, since its levels has been found elevated in different cancer types, such as multiple myeloma, gastric, lung, oesophageal and breast cancer [4-9] DKK-1 is a secreted inhibitor of the Wnt signalling pathway, which has tumorigenic and osteogenic potential [10-15].