There are conflicting opinions and evidence for the medicinal effects of GLA. The active constituent of EPO, which has been promoted to treat ailments including breast pain and eczema; such marketing was described by the "British Medical Journal" (BMJ) as ethically dubious – the substance was likely to be remembered as "a remedy for which there is no disease". Another single source suggests that Evening Primrose Oil with adjuvant vitamin E, may reduce breast pain. The BMJ said in 2003 that it was of no use in atopic dermatitis. The American Cancer Society said in 2010 that there was very little evidence for its effectiveness as an anti-cancer agent, for which it is sometimes promoted, and "neither GLA nor other GLA-rich supplements (such as evening primrose oil) have been convincingly shown to be useful in preventing or treating any other health conditions."