The two most common types of skin cancer are basal cell and squamous cell. Basal cell, which accounts for 90% of all U.S. skin cancer cases, begins in the skin’s inner layers and typically stays localized. Squamous cell begins in the outer layer and is more likely – though still unlikely – than basal cell to spread. Precancerous lesions called actinic (solar) keratosis may progress to squamous cell carcinoma if left untreated. Ultraviolet radiation from sun exposure is the primary cause of skin cancer. The artificial radiation people receive from sun lamps and tanning booths may also cause skin cancer. People with fair skin, freckling, red or blonde hair, and/or light-colored eyes have a higher risk of skin cancer.
P.S. Individuals who notice a change in the skin that lasts longer than two weeks should seek medical attention.