Study Rules Out UVA as Direct Cause of Melanoma

According to a recent study from The University of Texas MD Anderson Cancer Center, ultraviolet A (UVA) exposure in early life is no longer considered a direct cause of melanoma. The study, which tested UVA and UVB exposure on fish, found that there was no connection between UVA exposure at a young age and melanoma development and that UVA is unlikely to have contributed to the rise in occurrences of melanoma over the past 30 years.

While the study disconfirms any direct link between UVA exposure and melanoma, UVA rays are by no means harmless. UVA is considered a carcinogen and can suppress the immune system as well as cause premature aging of the skin. The researchers also stated that it is possible that continued exposure to UVA could expedite the progression of cells that are
already pre-cancerous.

The study examined the effects of UVA and UVB light on melanoma-prone fish during the first 5-10 days of their life. While the fish exposed to the UVB light had a 43% frequency of melanoma, the control group had an 18.4% frequency and the fish exposed to UVA had only a 12.4% frequency.

In 1993, a crucial study linked UVA exposure to melanoma. Up until that point sunscreens only protected against UVB rays. This turned into a massive public health concern knowing that UVA makes up 90% of the ultraviolet spectrum. This study caused many people to believe that the high rate of melanoma over the past 30 years was linked to early UVA exposure prior to updates made to sunscreen.

The University of Texas researchers were unable to duplicate the results of the 1993 study performed using the mammalian model. In hindsight, there were numerous problems with the research and sample sizes previously use.  Using a larger sample size to obtain stronger conclusions, The University of Texas researchers did not have the same findings about the effect of UVA on melanoma using the mammalian model.

The revamped mammalian study found that UVA may encourage melanin free radicals that react with DNA to form oxidative damage that will indirectly lead to melanoma, however, UVB exposure was found to directly damage DNA. No direct link between UVA and melanoma was found.

While UVA exposure has been ruled out for directly causing melanoma, further research is still needed to understand what type of indirect damage it may cause. Future studies may prove that UVA and UVB work symbiotically to cause or increase chances of melanoma.  No matter what, I highly recommend to keep sun exposure to a minimum and always wear sunscreen!