In Utero Exposure to Cadmium, Mammary Gland Development, and Breast Cancer Risk

Exposures to estrogen-mimickers correlate strongly with biomarkers of breast cancer risk in epidemiological and animal studies. The heavy metal cadmium activates ERa and the androgen receptor. Food sources of Cd include wheat, soy, rice, sunflower and flax seeds. Because the half-life of cadmium in the mammalian body is 20 years its endocrine-disrupting effects are long-lasting. We hypothesized that in utero exposure to low doses of dietary cadmium, would be associated with post-natal changes in puberty on-set, mammary development and tumour incidence. To test these hypotheses we exposed pregnant rats to a diet consisting of low cadmium levels throughout pregnancy. After parturition, all groups were switched to standard rodent chow. We chose two time-points to examine mammary development post-natal day 28 pre-pubertal and post-natal day 50 pubertal.