Combination of two carcinogens doubles risk of cancer

Washington, July 01: Low doses of arsenic and estrogen together- even at levels low enough to be considered “safe” for humans if they were on their own – can cause cancer in prostate cells, a new study led by an Indian-origin researcher has revealed.

According to Kamaleshwar Singh, an assistant professor at The Institute of Environmental and Human Health (TIEHH) at Texas Tech, the findings could have an impact on health regulations regarding the “safe” doses of these chemicals and others.

Singh said that unlike stronger chemicals that do major damage to the DNA in a cell, such as benzene, arsenic and estrogen aren’t major mutagens.

Instead, their presence tends to stop certain genes from expressing. The process is called DNA hypermethylation.

In the experiment, human prostate cells were treated about once a week for six months with arsenic, estrogen and a combination of the two. Many of the tests involved levels of arsenic, estrogen or both at levels considered safe by the Environmental Protection Agency.

Singh’s doctoral student, Justin Treas, said the two chemicals stopped the MLH1 gene, which is responsible for sending the signal to start the self-destruct sequence when a cell is damaged.

Because the self-destruct couldn’t activate, the cells became cancerous after exposure.

It was found that with the lower dose not killing the cell, it’s causing damages that go under the cell’s radar.

The research suggested that when you have two compounds together, lower doses could be more serious problem.

The study was published online in the peer-reviewed journal The Prostate. (ANI)