Photo of a breast self exam
The heavy metal cadmium, found in food, water, cigarette smoke and cosmetics, is an estrogen mimic

Cadmium linked to aggressive breast cancer growth

24 April, 2012

Natural Health News — New evidence suggests that breast cancer cells become increasingly aggressive the longer they are exposed to small concentrations of the heavy metal cadmium.

The study from the Dominican University of California was presented recently at the annual meeting of the American Society for Biochemistry and Molecular Biology in San Diego, California.

A handful of studies in recent years show that cadmium could play a significant role in the development of breast cancer. However, this study is unique in that it focuses on the effects of prolonged, chronic exposure rather than acute, high dose exposure.

Cadmium is produced mainly as a byproduct from mining, smelting and refining sulfidic ores of zinc, lead and copper. Rocks mined to produce phosphate fertilisers also contain varying amounts of cadmium. It also is found in rechargeable batteries and cigarette smoke. Cadmium enters the body through consumption of contaminated food, water or inhalation of cigarette smoke.

“Many of us are exposed to very low levels of cadmium from the environment on a daily basis, and our research shows that even small concentrations of this metal at prolonged exposures can cause breast cancer cell growth,” says lead researcher Maggie Louie, associate professor of biochemistry.

An estrogen mimic

Breast cancer results from the abnormal growth of the cells in the mammary gland. The normal growth of mammary gland epithelial cells is modulated by the circulating levels of estrogen, a hormone produced by the ovaries.

The activity of estrogen is stimulated by the estrogen receptor (ER). Heavy metals such as cadmium can act as endocrine disruptors and mimic estrogen, thereby disrupting the hormone dependent pathways.

“The relationship between cancer and chronic exposures at low levels is important to understand because most people are not exposed to high levels of heavy metals, unless they work in manufacturing plants that deal with such metals,” said Louie.

“Understanding the role that cadmium plays in the progression of breast cancer is extremely important in order to find better ways to prevent the disease from advancing. Ninety percent of cancer deaths are associated with the cancer spreading to other parts of the body. If we can prevent the tumour from spreading, we have a better chance of treating cancer,” she added.

Not the first study to show this effect

When most people think of the link between environmental agents and cancer, they think of how these substances can cause cancer. However the idea that exposure to environmental pollutants can make cancer more aggressive is not new.

In 1999 preliminary evidence from researchers at the Medical College of Wisconsin were amongst the first to suggest that they also act on already established cancers.

The scientists found that aggressive prostate cancer cells were different in their genetic make-up from dormant cells, and that environmental pollutants – such as heavy metals, cigarette smoke, pesticides, or car and truck emissions – triggered them to attack surrounding tissue and thereby spread more rapidly through the body.

They also found that these same pollutants may also turn non-aggressive prostate cancer cells into killer cells.

It makes you wonder just how long it might take for the Precautionary Principle to kick in and for doctors – and environmental regulators – to act to protect a vulnerable public.