PTCH1 and gastrointestinal stromal tumor: While both cell lines lack expression of SHH and IHH (data not shown), we confirmed that the lines express high levels of PTCH1, SMO, GLI2, and GLI3. GIST882 had 3.3-fold higher PTCH1, 2.0-fold higher SMO, and 6.0-fold higher GLI2 mRNA levels, as well as 2.2-fold lower GLI3 mRNA expression relative to GIST-T1 (Figure 1A).