Several Mycotoxins From Molds Are Carcinogens Or Suspected Carcinogens

Several mycotoxins are considered carcinogens (cancer causing chemicals) or possible carcinogens. The International Agency for Research on Cancer (IARC) has classified several mycotoxins as carcinogens or possibly carcinogens as follows:

1. AFLATOXINS- Carcinogenic to Humans- Produced by Aspergillus flavus and several other Aspergillus species. Aflatoxins commonly contaminate staple foods like grains (especially corn) and legumes (especially peanuts). Aflatoxin contamination in especially common in sub-Sahara Africa and tropical parts of Asia. Aflatoxins are some of most carcinogenic chemicals known.

Alfatoxins have been proven carcinogenic in many animals. Aflatoxins are known to increase risk of cancer by several mechanisms including forming adducts (binding products) with DNA, inactivating the p53 tumor suppressing genes, and altering other genes involved in cancer metabolism including N-ra and Ck-ras. Exposure to aflatoxins in foods and infection with hepatitis B has a synergistic (ie. more than additive) effect in promoting liver cancer. As reported earlier, foodborne exposure to aflatoxins are estimated to cause 25,500 to 155,000 new cases of liver cancer annually.

2. OCHRATOXINS- Possibly Carcinogenic to Humans- Produced by a number of Aspergillus and Pencillium species. Ochratoxins are commonly found in many foodstuffs and in water damaged indoor environments. Ochratoxins have been proven to cause liver and kidney cancer in mice and rats. Much recent research has also indicated that ochratoxins can increase risk of cancer by several mechanisms including forming ochratoxin-DNA adducts, causing oxidative stress, protein synthesis inhibition, and causing difficulties with cell division (mitosis).

Many researchers believe ochratroxins should be placed in the “Carcinogenic to Humans” category. FUMONISIN B1, B2, FUSARIN- Possibly Carcinogenic to Humans- Produced by a number of Fusarium species and often contaminate food stuffs. Some animal studies have found fuminosins to be carcinogenic. STERIGMATOCYSTIN- Possibly Carcinogenic to Humans- Produced by many Aspergillus species- up to 1% of the dry mass of Aspergillus versicolor consists of sterigmatocystin. Sterigmatocystin is Immunotoxic and may be carcinogenic in a similar fashion as aflatoxins OTHER POSSIBLE CARCINOGENIC MYCOTOXINS. Many other mycotoxins are currently being evaluated for possible carcinogenic effects including the following mycotoxins:

– Citrinin
– Cyclochlorotine
– Deoxynivalenol (also know as DON or vomittoxin)- Produced by Fusarium molds- and frequently contaminates human and animal feeds- causes nausea, headaches, vomiting.
– Kojic acid- Found in malting rice and rice wine.
– Luteoskyrin
– Nivalenol
– Patulin- Common mycotoxin frequent found on apples, pears, grapes, juice, wine3
– Penicillic Acid
– Regulosin
– T-2 Toxin
– Zearalenone- An endocrine disrupting mycotoxin produced by Fusarium species. Zearalenone implicated in producing early puberty in girls who eat foods with zearalenone contamination.

References / Sources

1. Ostry V, Malir F, Toman J, Grosse Y. Mycotoxins as human carcinogens-the IARC Monographs classification. Mycotoxin Res 2016.

2. Liu Y, Wu F. Global burden of aflatoxin-induced hepatocellular carcinoma: a risk assessment. Environ Health Perspect 2010;118(6):818-24.

3. Brase S, Encinas A, Keck J, Nising CF. Chemistry and biology of mycotoxins and related fungal metabolites. Chem Rev 2009;109(9):3903-90.

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