Because GLI1 is a target gene of the HH signal pathway39, we further analyzed the expression of SHH in keloid tissue and found enhanced protein expression of SHH in keloid tissue and surrounding normal-looking tissues compared with normal skin and mature scar from a non-keloid patient (Fig. 3a–d) and by immunocytochemistry, SHH was mainly expressed in the cytoplasm (Supplementary Fig. 5). Here, SHH is linked to keloid.