PTCH1 and neoplasm: Remarkably, expression of the receptor, Ptch1, and its homologue, Ptch2, as well as the main intestinal ligand, Ihh, was dissociated from attenuated downstream Hh signalling (Fig. 1e), whereas all tumours demonstrated increased Wnt activity, as expression of the Wnt targets, Axin2 and Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) was upregulated (Fig. 1e).