GLI1 and neoplasm: However, when we measured the HH signaling activity in the cSCC samples GLI1 specific in situ hybridization using the RNAscope® technology (for positive controls see Supplementary Figures S1B, C), we found GLI1 expression in discrete tumor nests in approximately 50% of tumors with a rather heterogeneous pattern (Figures 1A, B, lower right panels).