NYU Langone logoUVA radiation is believed to tremendously damage the skin but this harm may be reduced or completely avoided by using a sun block. Experts from the NYU School of Medicine claim that UVA radiation damages the DNA in human melanocyte cells further leading mutations to cause melanoma.

It is assumed that melanin is a substance present in melanocytes. This melanin supposedly protects the skin from the ultraviolet rays of the sun by darkening it. The authors mentioned that the melanin is more accessible to UVA radiation than normal skin cells. This is because they cannot repair themselves very well.

Moon-shong Tang, PhD, professor of environmental medicine, pathology and medicine at NYU School of Medicine and a member of the NYU Cancer Institute enlightened, “For the first time, UVA rays have been shown to cause significant damage to the DNA of human melanocyte skin cells. And because melanocytes have a reduced capacity to repair DNA damage from UVA radiation, they mutate more frequently, potentially leading to the development of melanoma.”

While conducting the study, investigators apparently exposed lightly and darkly pigmented human melanocytes to UVA radiation. They then evaluated DNA damage and the ability of these cells to repair damaged DNA. The authors claimed to be successful in identifying DNA damage in all melanocyte cells. They further revealed that these cells were unable to repair the damage. When normal skin cells were exposed to UVA light no harm was seemingly discovered in their DNA.

Dr. Tang commented, “Identifying the underlying causes of melanoma allows researchers to develop new ways to assess a person’s risk of melanoma, prevent the disease and aid in the design of more effective treatments.”

DNA damage is assumed to be led by sunlight in the form of UVA radiation, as it is responsible for the oxygen caused in melanocytes. Transcription and DNA replication in melanocytes may be adversely damaged due to this oxidative DNA. UVA-induced oxidative DNA damage in melanocytes and the inherently reduced repair capacity in these cells are assumed to be the two key factors responsible for melanoma on the skin.

Dr. Tang explained, “Melanoma, the deadliest form of skin cancer, continues to increase at a rate of 3 percent a year. This research highlights the necessity of limiting UVA radiation by avoiding excessive sunlight, tanning and sun beds.”

Astonishingly melanoma can also develop in areas that are never exposed to sunlight. This is because usually melanocytes seem to display limited capacity for repairing any DNA damage. They have a higher mutation frequency rate and seem to be more assessed in developing melanoma even in the absence of the effects of the sun.

The study was published online and will appear in the July 6, 2010 issue of Proceedings of the National Academy of Sciences.