Aflatoxin B₁: An Immunomodulator and Cancer Agent

The type I interferon signaling pathway of the innate immune system plays a key role in the first line of defense in eliminating pathogens and other chemical agents that are introduced into the body and is also known to exhibit the anticancer properties. Therefore, any agent being chemical or components of microorganisms that tend to inhibit or suppress the type I interferon response pathway will weaken the innate immune system and predispose individuals to infectious agents and cancers. Aflatoxin B1 has been reported to modulate the immune system by suppressing inflammatory cytokines, monocytes, lymphocytes and the type I interferon signaling response pathway. Aflatoxin B1 contamination of food is very high in most sub-Saharan African countries. Aflatoxin B1 contamination of diet coupled with subsequent prolonged heavy exposure is one of the major risk factors for the development of hepatocellular carcinoma. Aflatoxin B1 is known to cause hepatocellular carcinoma by inducing mutation in the tumor suppressor gene TP53. We present in this review the mechanism by which aflatoxin B1 inhibits the type I interferon signaling pathway thus pre-disposing exposed individuals to cancers and other infections.