Activation of the Hedgehog and Wnt/β-Catenin Signaling Pathways in Basal Cell Carcinoma

In basal cell carcinoma (BCC) tumorigenesis, interaction between Hedgehog (Hh) and Wnt/β-catenin (Wnt) signaling pathways has been investigated, but not completely elucidated. Here, a case of sporadic BCC in an 80-year-old man is presented, and the effectiveness of SMO inhibitors in case of relapse is predicted. The aim of this study was to determine whether the SMO inhibitors can be effective in treating this individual should the tumor recur in the future. Immunohistochemistry (IHC) was performed in a tumor and the adjacent skin tissue from the patient. IHC within the same BCC tissue specimen revealed that Glioma-associated oncogene 1 (GLI1) and Smoothened (SMO) in the Hh signaling pathway and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in the Wnt signaling pathway were overexpressed. Hh and Wnt signaling pathways were activated. These findings suggest that the patient might be resistant to treatment with SMO inhibitors because of the interaction between Hh and Wnt signaling pathways. Overexpression of GLI1 leads to transcriptional activation, making it an attractive molecular target for anticancer therapy owing to the downstream effectors of the cascade.