A method for modulating Sonic hedgehog (Shh)-mediated signalling and proliferation based on agents that modulates the binding of GAS1, BOC and/or CDON to Ptch1 is disclosed. Methods and compositions for treating cancer using agents that inhibit the binding of GAS1, BOC and/or CDON to Ptch1 are also disclosed. Methods for identifying agents that may be used to inhibit Shh-mediated signalling/proliferation and cancer based on their capacity to inhibit the binding of GAS1, BOC and/or CDON to Ptch1 are also disclosed.
