Eating higher amounts of fish, specifically tuna and non-fried fish, appears to increase the risk of malignant melanoma, according to a Brown University study of 491,367 U.S. adults published in the journal Cancer Causes and Control. Examining 15 years of data, the researchers found that compared to subjects with a median daily fish intake of .11 ounces, those with a median daily intake of 1.5 ounces had a 22 percent higher risk of malignant melanoma and a 28 percent increased risk of melanoma in situ, characterized by abnormal cells in the outer layer of the skin. “We speculate that our findings could possibly be attributed to contaminants in fish, such as polychlorinated biphenyls, dioxins, arsenic and mercury,” says study author Eunyoung Cho, an associate professor of dermatology and epidemiology. Pending further research on the underlying biological mechanisms, the authors did not recommend any changes to fish consumption.