IHC and immunoblotting were performed as we previously described 10 (link), 68 (link). Antibodies for IHC included p-STAT3 (Y705) antibody (Cell Signaling; #9145; 1:50), and rabbit polyclonal GLI1 and tGLI1 antibodies that we developed and validated 10 (link), 26 , 68 (link). Antibodies for immunoblotting included p-STAT3 (Y705) antibody (Cell Signaling, 1:1,000), STAT3 rabbit polyclonal antibody (Santa Cruz; C20; 1:1,000), α-tubulin and β-actin mouse monoclonal antibodies (Sigma), and rabbit polyclonal GLI1/tGLI1 antibody (Cell Signaling, 1:1,000). For IP, cells were transfected with flag-tagged GLI1, tGLI1 or STAT3 mutants, stimulated with 100 ng/ml EGF and 100 ng/ml SHH for 2 hrs, washed, fractionated, and precleared with protein G-agarose (Sigma; A2220). Precleared lysates were incubated with anti-flag M2 affinity gel or mouse IgG at 4°C overnight with gentle agitation. Pellets were collected, washed and subjected to SDS-PAGE and WB analysis. STAT3 IP was performed using antibodies from Santa Cruz (C-20). GLI1 and tGLI1 immunoprecipitation was performed using a GLI1 antibody (Santa Cruz, H-300) that recognizes the COOH-terminal end and, therefore, pulls down GLI1 and tGLI1.