DKK1 and breast carcinoma: In addition, two groups recently reported frequent SFRP1 methylation in primary breast tumours (Lo et al, 2006; Veeck et al, 2006), and Bafico et al (2004) clearly demonstrated a novel autocrine mechanism leading to constitutive Wnt signalling in breast cancer, which could be suppressed by SFRP1 and DKK1.