GLI2 and skin basal cell carcinoma: Therefore, primary cilia suppress the progression of SHH medulloblastoma caused by the mutation/amplification of GLI2.156 The dual and opposing roles of primary cilia are also observed in basal cell carcinoma (BCC), a skin cancer caused by dysregulated hedgehog signaling.157, 158, 159 Primary cilia are expressed in BCC caused by activated form of SMO and ablation of primary cilia inhibits the progression of BCC.