GLI1 and colonic neoplasm: Moreover, the extracellular Wnt antagonists Sfrp1 and Sfrp2 are upregulated by Shh-Gli signalling in different experimental systems [159-161] and nuclear accumulation of the Wnt transducer β-catenin and the Shh transducer Gli1 are inversely correlated in a human colon cancer cell line [162].