Basal-cell carcinoma
Basal-cell cancer is a very common skin cancer. It is much more common in fair-skinned individuals with a family history of basal-cell cancer and increases in incidence closer to the equator or at higher altitude. There are approximately 800,000 new cases yearly in the United States alone. Up to 30% of Caucasians develop basal-cell carcinomas in their lifetime. In Canada, the most common skin cancer is basal-cell carcinoma (as much as one third of all cancer diagnoses), affecting 1 in 7 individuals over a lifetime.
Nevoid basal-cell carcinoma syndrome
First described in 1960 by Gorlin and Goltz, NBCCS is an autosomal dominant condition that can cause unusual facial appearances and a predisposition for basal-cell carcinoma, a type of skin cancer which rarely spreads to other parts of the body. The prevalence is reported to be 1 case per 56,000–164,000 population. Recent work in molecular genetics has shown NBCCS to be caused by mutations in the "PTCH" (Patched) gene found on chromosome arm 9q. If a child inherits the defective gene from either parent, he or she will have the disorder.