Editorial: Preventing cancer

Tuesday, May 15, 2007 | 7:32 a.m.

A research team recently reported that more than 200 chemicals have been linked to breast cancer in animals and said that human exposure to breast cancer carcinogens is "widespread," the Los Angeles Times reported Monday.

"These compounds are widely detected in human tissues and in environments, such as homes, where women spend time," the researchers wrote in a study funded by Susan G. Komen for the Cure, a group that stresses breast cancer prevention.

The researchers are calling for a greater scientific emphasis on animal tests because there are significantly more studies on animals than there are on humans when it comes to breast cancer and its causes. Culling through hundreds of animal tests, the researchers found 216 chemicals linked to the disease. Of those, 97 are chemical compounds that people regularly come in contact with, including gas and diesel emissions, a chemical in chlorinated drinking water, cosmetic compounds, shampoo, food additives and pharmaceuticals.

Researchers noted that there could be more chemicals to add to the list because only about 1,000 of the 80,000 chemicals registered in the United States have undergone extensive animal testing to determine whether the chemicals induce cancer or mutate DNA.

This study does not definitively link chemicals to human cancer, but the report notes that regulators typically overlook animal tests.

Animal testing, the researchers argue, is the primary way science can understand and anticipate how chemicals will affect humans. Besides, they say, "all known human carcinogens ... are also carcinogenic in animals."

Cancer is a horrific disease, and breast cancer is the leading killer of women in their mid-30s to their early 50s, which is all the more reason that more research should be commissioned in this area.