Superfund Research Program

June 2019

New research from the University of California, Berkeley Superfund Research Program (UC Berkeley SRP) Center identifies a set of eight key characteristics for male reproductive toxicants (MRTs) – chemicals that cause negative effects on the male reproductive system. Key characteristics explain the actions of certain chemicals inside the body.

Martyn Smith, Ph.D., director of the UC Berkeley SRP Center and co-leader of the Research Translation Core, explained key characteristics and the benefits of identifying them at the Converging on Cancer Workshop in Washington, D.C.

"A cancer hallmark is the biology of the cancer cell, while a key characteristic is what makes [that] biology happen," said Smith. He then explained how key characteristics can be used to make predictions about different chemicals.

His earlier work on key characteristics of human carcinogens paved the way for the development of key characteristics for MRTs. Collaborating with a group regulatory experts and scientists, the team used lists of chemicals known to target the male reproductive system, including toxins like cadmium and phthalates, pharmaceuticals, and drugs of abuse like opiates. Then they analyzed outcomes reported in numerous research studies.

Some of the key characteristics they identified included causing DNA damage, causing inflammation, and altering the function of hormones. They noted that chemicals showing evidence for one or more key characteristics are likely, though not guaranteed, to be harmful to male reproductive health.

By identifying key characteristics, researchers will be better able to identify, organize, and summarize the potential health risks of different chemicals. According to the authors, the approach may also be useful in a data science approach to prioritizing chemicals for further study.

male reproductive toxicity
The diagram shows the eight key characteristics of MRT. For example, some characteristics include altering the development, function, or death of cells; causing DNA damage; or causing inflammation. For additional details, please refer to the original article. (Image from: Arzuaga X, Smith MT, Gibbons CF, Skakkebæk NE, Yost EE, Beverly BEJ, Hotchkiss AK, Hauser R, Pagani RL, Schrader SM, Zeise L, Prins GS. 2019. Proposed Key Characteristics of Male Reproductive Toxicants as an Approach for Organizing and Evaluating Mechanistic Evidence in Human Health Hazard Assessments. Environmental Health Perspectives 127(6):65001 doi: 10.1289/EHP5045)