July 22, 2015

UAMS Researchers Assess Cancer Risks of Exposures to Low-Dose Chemical Mixtures

U A M S post doctoral fellow Isabelle R. Miousse, P h D, and C O P H Assistant Professor Igor Koturbash, P h D

Isabelle R. Miousse, Ph.D., and Igor Koturbash, Ph.D.

Amidst a global cancer epidemic, a task force of 174 scientists from prominent institutions in 28 countries was assembled in 2013 by a non-governmental organization called “Getting to Know Cancer” to investigate longstanding concerns over the linkages between exposures to mixtures of commonly encountered chemicals and the development of cancer. Igor Koturbash, M.D., Ph.D., Assistant Professor in the Department of Environmental and Occupational Health in the UAMS Fay W. Boozman College of Public Health, and Isabelle R. Miousse, Ph.D., UAMS post-doctoral fellow, were among these scientists.

From the thousands of chemicals to which the population is now routinely exposed, the scientists selected 85 prototypic chemicals that were not considered to be carcinogenic to humans and they reviewed their effects against a long list of mechanisms that are important for cancer development. Working in teams that focused on various hallmarks of cancer, the group found that 50 of those chemicals support key cancer-related mechanisms at levels of environmental exposure commonly experienced. This supports the idea that chemicals may be capable of acting in concert with one another to cause cancer, even though low-level exposures to these chemicals individually might not be carcinogenic.

“We are exposed to a whole bunch of environmental chemicals on an everyday basis,” says Dr. Koturbash. “Although these are the low-dose exposures, and we know a lot about the individual effects of these chemicals, there is not much that we know about their combined and additive effects, especially in regard to continuous, life-long exposures,” he added.

Dr. Koturbash and Dr. Miousse are the co-authors in two of the manuscripts that just have been published in a special issue of Carcinogenesis, devoted to this problem. (http://carcin.oxfordjournals.org/content/36/Suppl_1).

This was the first time that this large-scale problem has ever been considered by interdisciplinary teams that could fully interpret the full spectrum of cancer biology and incorporate what is now known about low-dose chemical effects. In light of this evidence, the task force is calling for an increased emphasis and support for research on low-dose exposures to mixtures of environmental chemicals.

Task force scientists noted that current estimates suggest that as many as one in five cancers may be due to chemical exposures in the environment that are not related to personal lifestyle choices. So the effects of exposures to mixtures of commonly encountered chemicals need to be better understood, if we hope to reduce the incidence of cancer.