The cloning of vertebrate homologues of the Drosophila segment polarit
y gene patched has led to confirmation of a role for the multipass tra
nsmembrane protein which it encodes as a receptor for secreted signall
ing proteins of the Hedgehog family. In addition, human patched has be
en identified as a tumour suppressor gene implicated in basal cell car
cinomas and medullablastomas.