GLI1 and skin basal cell carcinoma: The results from these studies also suggest that oncogenic HH signalling can drive BCC initiation in several different epithelial stem‐ and progenitor cell populations in mouse skin, including SCs in the bulge and isthmus regions of the HF and GLI1‐positive cells in touch dome epithelia, although the tumor morphology and the final outcome of BCC development are also influenced by the mutated HH signalling pathway member, and the strength of oncogenic HH signalling.24, 25, 26