PTCH1 and skin basal cell carcinoma: Lastly, BCC pathogenesis has been linked to several genetic alterations, including mutations in the Hedgehog pathway (Patched 1 (PTCH1), Smoothened (SMO]), the tumour suppressor Tumour Protein p53 (TP53), proto-oncogenes of the Rat Sarcoma (RAS) family, and germline variants in the Melanocortin 1 Receptor (MC1R) gene [4,5].