Anti-microbial in household products promotes liver cancer in mice, study shows

By Melissa Schenkman

Triclosan (TCS), a popular anti-microbial ingredient in soaps and other common household products, may promote tumor growth in the liver of mice, according to researchers in University of California San Diego School of Medicine.

The study undertaken by chemistry professor Robert Tukey and his colleagues examined the potential biological impacts of TCS given to mice.

“The mechanisms we uncovered in mice are the same biological processes that exist in humans. And that is important to appreciate,” said Tukey, lead author of the study published recently in the Proceedings of the National Academy of Sciences. “Yet, we don’t know if TCS will impact human liver function the same way as we see it in mice. So comparing it to human exposure is entirely premature.”

TCS has been added to an increasing number of products over the past two decades and has been found as a contaminant in waterways across the U.S., according to Tukey. “It is an ubiquitous environmental toxin,” he said.

Two groups of mice were fed a daily diet containing triclosan that ranged from 20 mg/kg body weight to 3000 mg/kg of body weight. The group that already had liver tumors showed an increase in the size and number of their tumors after triclosan exposure. The study was conducted over eight months.

“This property defines TCS as a tumor promoter, since the end result of long term exposure is an increase in tumor development,” Tukey said.

As for the group of mice without tumors, exposure to TCS, initiated changes in liver cells including liver fibrosis and regeneration. Both processes are observed in humans prior to developing liver cancer.

Researchers also found that TCS could induce kidney fibrosis in the mice.

“It is a new mechanism by which environment can cause cancer,” said study co-author Bruce Hammock, professor in University of California-Davis Department of Entomology and the UCD Comprehensive Cancer Center.

What might this mean for the consumer of everything from shampoos to soaps to toothpaste? The exposure to TCS in humans occurs topically through use of products containing TCS, while the mice ingested the ingredient in their food. “Experts not involved in the study cautioned that mice were eating and drinking the tryclosan in their food and water in ‘super high concentrations,'” according to Sydney Lupkin of ABC World News.

The public has a choice when it comes to choosing its products, Tukey said. He added that the current study warrants further research.