Cadmium -- a heavy metal commonly found in cosmetics, food, water and air pollution – appears to make breast cancer tumors more aggressive, even in small concentrations, according to new research by the Dominican University of California.
The study, presented at the annual meeting of the American Society for Biochemistry and Molecular Biology in San Diego this week, shows exposure to cadmium for prolonged periods can cause breast cancer to become more virulent.
Past studies have shown high levels of acute cadmium exposure can increase the risk of cancer, but the new study is the first to focus on the dangers of chronic, low-level exposure to the common contaminant.
"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 lead researcher Maggie Louie. "Unfortunately, cadmium is all around us – it is in our food, our water, our makeup and our air.”
She added that understanding how cancer progresses, and becomes more aggressive, is key to managing the disease and keeping patients alive.
“Ninety percent of cancer deaths are associated with the cancer spreading to other parts of the body,” she noted. “If we can prevent the tumor from spreading, we have a better chance of treating cancer."
Louie noted breast cancer results from the abnormal growth of the cells in the mammary gland. Circulating levels of the female hormone estrogen typically regulate the normal growth of breast cells. But heavy metals such as cadmium can disrupt that process and, according to the new study, promote the development of more malignant characteristics in breast cancer cells.
Louie's research was funded by the National Cancer Institute at the National Institutes of Health.