PTCH1 and non-small cell lung carcinoma: In order to investigate if the lack of response to exogenous Shh in NSCLC cells was due to an improper reception of Shh ligand in these cells, we have evaluated the expression of the receptors Ptch1, Ptch2 and of Hhip, considered as a decoy receptor, in A549, H520 cells and CLL206 fibroblasts.