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It has been reported that UV radiation leads to local and systemic immunosuppression, due to DNA damage and altered cytokine expression. This has implications in cutaneous tumor surveillance. The Langerhans cells may undergo changes in quantity, morphology, and function due to UV exposure and may eventually become depleted. One proposed ...
According to the National Toxicology Program Report on Carcinogens from the US Department of Health and Human Services, broad-spectrum UV radiation is a carcinogen whose DNA damage is thought to contribute to most of the estimated 1.5 million skin cancers and the 8,000 deaths due to metastatic melanoma that occur annually in the United States.
One of the largest promoters of apoptosis is exposure to ultraviolet (UV) light. While UV light is essential to human life it can also cause harm by inducing cancer, immunosuppression, photoaging, inflammation, and cell death. [1] Of the various components of sunlight, ultraviolet radiation B (UVB) (290-320 nm) is considered to be the most harmful.
All bands of UV radiation damage collagen fibers and accelerate aging of the skin. Both UVA and UVB destroy vitamin A in skin, which may cause further damage. [67] UVB radiation can cause direct DNA damage. [68] This cancer connection is one reason for concern about ozone depletion and the ozone hole.
This process of absorption works to reduce the risk of DNA damage and the formation of pyrimidine dimers. UVA light makes up 95% of the UV light that reaches earth, whereas UVB light makes up only about 5%. UVB light is the form of UV light that is responsible for tanning and burning. Sunscreens work to protect from both UVA and UVB rays.
Ultraviolet is classified into near, medium and far UV according to energy, where near and medium ultraviolet are technically non-ionizing, but where all UV wavelengths can cause photochemical reactions that to some extent mimic ionization (including DNA damage and carcinogenesis). UV radiation above 10 eV (wavelength shorter than 125 nm) is ...
DNA photoionization is the phenomenon according to which ultraviolet radiation absorbed directly by a DNA system (mononucleotide, single or double strand, G-quadruplex…) induces the ejection of electrons, leaving electron holes on the nucleic acid. The loss of an electron gives rise to a radical cation on the DNA.
The primary cause of skin cancer is prolonged exposure to ultraviolet (UV) radiation from the sun or tanning devices. Skin cancer is the most commonly diagnosed form of cancer in humans. [ 11 ] [ 12 ] [ 13 ] There are three main types of skin cancers: basal-cell skin cancer (BCC), squamous-cell skin cancer (SCC) and melanoma . [ 1 ]