Association of Cadmium with Human Breast Cancer

ISEE-0560 Background and Objective: Cadmium is a known human carcinogen based on findings of lung cancer in exposed populations. A more controversial target site for cadmium is the human mammary gland, for which some studies indicate a link between cadmium exposure and cancer. Some authors suggest that cadmium is a new environmental estrogen that mimics the effects of estradiol in estrogen-responsive breast cancer cell lines. In order to assess an association of cadmium with human breast cancer, we examined cadmium concentration in urine and breast tissue of patients with breast cancer and non-malignant breast tumour. Methods: Cadmium was analyzed in the samples of urine and breast tissue of 57 breast cancer patients and 50 benign tumour patients. Two samples of breast tissue from each patient, i.e. tumour and some healthy tissue close to tumour were taken for the analysis. Cadmium was determined by atomic absorption spectrometry (Perkin-Elmer, Zeeman 3030). Estrogen receptors (ER) determined by immunohistochemical assay. Results: The mean cadmium concentration in breast cancer patients was 53.4 ng/g (95% CI = 42.2–64.6) for tumour sample and 20.1 ng/g (95% CI = 14.4–25.9) for healthy breast tissue sample (P < 0.001). In benign tumour patients the figures were following: 37.2 ng/g (95% CI = 23.3–51.1) and 32.1 ng/g (95% CI = 17.5–46.5) (P = 0.449). Cadmium concentration found in the sample of malignant tumour differed significantly from that in the sample of benign tumour (P < 0.001). Significantly higher concentration of cadmium determined in breast cancer patients with positive ER compare to that with negative ER (67.5 ng/g 95% CI = 48.7–86.2 vs. 42.5 ng/g 95% CI = 28.6–56.4, P = 0.035). There was a positive correlation between cadmium in the samples of breast tumour and urine (R = 0.3, P = 0.01). In breast cancer patients cadmium in urine correlated with number of cigarettes smoked during lifetime (R = 0.7, P = 0.02). Conclusion: The data obtained show a possible relationship between cadmium and breast cancer.