The role of Polybrominated Dyphenyls Ethers in thyroid carcinogenesis: is it a weak hypothesis or a hidden reality? From facts to new perspectives.

In the last decades, the incidence of thyroid cancer has increased faster than that of anyother malignant tumor type. The cause of thyroid cancer is likely multifactorial and a variety of bothexogenous and endogenous has been identified as potential risk factors. Polybrominated diphenylethers (PBDEs), used since the 1970s as flame retardants, are still widespread and persistentpollutants today, although their production was definitely phased out in the western countriesseveral years ago. Polybrominated diphenyl ethers are known endocrine disruptors, and theendocrine system is their primary target. Whereas animal studies have ascertained the ability ofPBDEs to affect the normal functionality of the thyroid, evidence in humans remains inconclusive,and only a few epidemiological studies investigated the association between exposure to PBDEsand thyroid cancer. However, a number of clues suggest that a prolonged exposure to thesechemicals might act a trigger of the most common malignancy of the endocrine system, whereasfurther studies with an advanced design are suggested.