"Skin cancer is the most common form of cancer in the United States" -- CDC
DNA Damage
Skin Cancer Types
Premature Aging
Ultraviolet (UV) radiation from the sun is responsible for the vast majority of skin cancers. Skin protects the inner parts of our body from exposure to UV but in the process our skin cells take the hit. When a ray of UV penetrates and strikes the DNA inside of a skin cell, it damages the DNA. Fortunately, the cell has a built in mechanism to repair DNA damage and the cell might then return to normal. However, the repair mechanism is prone to making mistakes. If a mistake is made and the DNA is repaired incorrectly, the result is a mutation. In contrast to DNA damage, which can potentially be repaired, mutations are irreversible and permanent. Sometimes, a mutation might occur in an oncogene. That’s a gene that’s capable of causing the cell to divide continuously and uncontrollably. When a cell is growing and multiplying out of control, that’s cancer. Because the sun’s UV rays are capable of causing mutations that result in skin cancer, UV is classified as a carcinogen.
Skin Cancer Types
The different types of skin cancer depend on which skin cell, and which genes within the cell, have been mutated. The topmost layer of the skin, the epidermis, is comprised of keratinocytes (the bricks) and melanocytes (the pigment producing cells). Melanoma is the skin cancer that is caused by mutations in melanocytes. Basal Cell Carcinoma and Squamous Cell Carcinoma are each due to mutations in keratinocytes and are together referred to as non-melanoma skin cancer (NMSC).There are additional rare types of skin cancer, and they may or may not be caused by the sun.
Skin Aging
The dermis is the second layer of the skin. It is comprised mainly of connective tissue containing collagen, elastic fibers, and the cells that make them. Any UV that gets past the epidermis is absorbed in the dermis beneath. Surprisingly, UV does not tend to cause cancer of the dermal cells but it does trigger the production of solar elastotic material. This substance accumulates over time, causing changes in the texture and quality of the dermis, with the most visible manifestations being wrinkles and a sallow, cobblestone, appearance.
