Clear face of a patient with basal cell nevus syndrome (BCNS) who is being treated with the drug vismodegib. BCNS, also known as Gorlin syndrome, is an inherited cancer syndrome. It increases the risk of developing a number of benign (non-cancerous) and malignant (cancerous) tumours, with the most common being multiple basal cell carcinomas (BCCs). BCC is a common form of skin cancer that is thought to be caused by the ultraviolet radiation in sunlight. It slowly destroys surrounding tissue, but seldom spreads to other parts of the body. Vismodegib inhibits the signalling pathways that lead to the formation of a BCC.