How UV radiation causes skin cancer?
Melanin is contained in different quantities in the different skin types in human. So, it is normal that their response to UV exposure also differs. The skin has been categorized by The United Nations and WHO into four types which are the burner, the tanner, the naturally brown and the naturally black. This is based on the minimum exposure rates without doing any harm.
We Indians come under group 3, naturally brown. It makes us highly vulnerable to the effects of UV rays as our skin is exposed to a UV index of 10 or above. In such instances, usage of shade, sunscreen, shirts and cap is recommended by a cancer specialist. The risk categories are further divided based on low rays, medium rays, high rays and very high rays. We Indians are in the very high-risk category at present.
The UV rays are filtered by the ozone layer. In the present days, it is a very worrisome fact as the ozone layer is depleting. The main factor that causes skin cells to become cancer cells is exposure to UV radiation.
Too much UV radiation from the sun or other sources such as solaria (solariums, sunbeds and sunlamps) cause almost all skin cancers (95% of melanoma skin cancers and approximately 99% of non-melanoma skin cancers).
In the cells in the epidermis (the top or outer layer of the skin), skin cancer develops. UVA and UVB rays make up UV radiation. They cause permanent damage to the cells as they are able to penetrate the skin.