Given that the Hedgehog pathway has been shown to control the development of the mouse gut mesenchyme [11], we sought to determine whether two commonly studied murine models of the mesenchymal tumor GIST express key Hedgehog signaling components (Shh, Ihh, Ptch1, Smo, Gli1, Gli2, Gli3). Here, PTCH1 is linked to gastrointestinal stromal tumor.