Friday, October 9, 2015

Malignant Melanoma Metastasize Faster with Antioxidants

Melanoma, also known as malignant melanoma, is a type of cancer that develops from the pigment-containing cells known as melanocytes. Melanomas typically occur in the skin but may rarely occur in the mouth, intestines, or eye. Melanomas are usually caused by DNA damage resulting from exposure to ultraviolet (UV) light from the sun. Genetics also play a role. About 20-25% develop from moles where a history of affected family members, or ones with poor immune function are at greater risk.

Melanoma is the most dangerous type of skin cancer. Treatment is typically removal by surgery. In those with slightly larger cancers nearby lymph nodes may be tested for spread. Most people are cured if spread has not occurred. In those in whom melanoma has spread, immunotherapy, biologic therapy, radiation therapy, or chemotherapy may improve survival. The likelihood that it will come back or spread depends how thick the melanoma is, how fast the cells are dividing, and whether or not the overlying skin has broken down.

Researchers at Sahlgrenska Academy, University of Gothenburg, demonstrated in January 2014 that antioxidants hastened and aggravated the progression of lung cancer. Mice that were given antioxidants developed additional and more aggressive tumors. Experiments on human lung cancer cells confirmed the results. The group now report that antioxidants in mice double the rate of metastasis in malignant melanoma. Mice that were given antioxidants developed additional and more aggressive tumors. One of the fastest expanding types of cancer in the developed world, malignant melanoma has a high mortality rate - which is one reason that researchers at Sahlgrenska Academy were so anxious to follow up on the lung cancer studies.

Their findings reveal the following:

a: As opposed to the lung cancer studies, the primary melanoma tumor was not affected.

b: Antioxidant boosted the ability of the tumor cells to metastasize.

c: Metastasis is the cause of death in the case of melanoma.

d: The primary tumor is not dangerous per se and is usually removed.

Free radicals are believed to cause cancer, and there is large volume of literature to support this theory. So it was simply assumed that antioxidants, which destroy free radicals, provide protection against the disease. Found in many nutritional supplements, antioxidants are widely marketed as a means of preventing cancer. The researchers from University of Gothenburg have added a condition apply logo to use of antioxidant which now says “antioxidants protect healthy cells from free radicals that can turn them into malignancies but may also protect a tumor once it has developed”. Moreover, experiments on cell cultures from patients with malignant melanoma confirmed the new results.

The authors conclude “Our current research combined with information from large clinical trials with antioxidants suggests that people who have been recently diagnosed with cancer should avoid such supplements.”

The next task for this group is study the roles of lotions in melanoma progression as skin and suntan lotions sometimes contain beta carotene or vitamin E, both of which could potentially affect malignant melanoma cells in the same way as antioxidants in nutritional supplements.

Article Citation: Bergo, M. O.; et. al. Antioxidants can increase melanoma metastasis in mice. Science Translational Medicine 2015, 7(308), 308re8. DOI: 10.1126/scitranslmed.aad3740