Which Pesticides Create Precancerous Changes in Thyroid Cells?


pesticidesBy Gary Pepper, M.D.
Last week I posted a few highlights from the just concluded International Thyroid Congress. One of the research papers presented at the meeting generated particular concern. Endocrinologists and scientists at UCLA Medical Center led by Dr. Jerome Hershman investigated the potential for pesticides to damage the DNA of thyroid cells. The group focused on double strand breaks, the type of damage that could eventually lead to cancer. This is a particularly relevant point due to the explosion in newly diagnosed thyroid cancers being reported in many areas of the world. The increase is likely related, at least in part, to improved diagnostic techniques for thyroid cancer but could also represent environmental influences.
To achieve this the UCLA team utilized a technique capable of rapid screening of a large number of compounds for their ability to damage thyroid cell DNA in a manner known as double strand breaks, which could potentially lead to cancer. Out of 309 compounds tested the following caused double strand breaks in DNA; abamectin, amitraz, captafol, captan, difenconazole, diquat, fluazinam, naled, prallethrin, prodiamine, propargite, rotenone, tebupirimfos, TCDD (dioxin), tribufos, and triclosan.
A quick search reveals that these are easily obtainable products. For example the first, abamectin, is sold under these brand names; Abba, Abathor, Affirm, Agri-Mek, Avid, Dynamec, Epi-Mek, Genesis Horse Wormer, Reaper, Vertimec, CAM-MEK 1.8% EC (cam for agrochemicals), Zephyr and Cure 1.8 EC. Amitraz is used in dog collars and as a pet “dip”. Conceivably your pet or your neighbors animal could have been treated with this compound. Prallethrin is an insect repellant available at Walmart in the brand Hot Shot. Rotenone is the second most common insecticide used by organic farmers. So it goes with the rest of these chemicals.
Although there is no proof these compounds lead to thyroid cancer, it does highlight the need for better understanding of how these everyday chemicals in our environment can impact us. For now it seems prudent to read the handling instructions of pesticides carefully and stay alert for circumstances where you or your family could come into contact them. We wait further clarification from scientists like those at UCLA, to fully assess the risk we all face from these common products.

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