Association of cadmium with human breast cancer

The carcinogenic potential of cadmium might be affected by several factors such as smoking, hormones and presence of other metals, such as selenium and zinc. Cadmium was analyzed in breast-fat tissue of 43 breast cancer patients and 32 healthy control subjects. Patients were thoroughly characterized according to such variables as stage of cancer, smoking habits, and number of children. Correlation of cadmium levels with these variables, with hormone receptors, and with previously reported selenium and zinc were all analyzed. The mean cadmium concentration found in breast cancer patients (20.4 +/- 17.5 micrograms/g) did not differ significantly from that of the healthy controls (31.7 +/- 39.4 micrograms/g). However, unexpectedly high concentrations of cadmium (3.2-86.9 vs. 0.1-160.4 micrograms/g) were found in breast samples, which may indicate that cadmium binding proteins exist in human breast tissue. Correlation of cadmium with smoking rate of cancer patients was positive (Rs = 0.0505, p < 0.05). Correlation of cadmium with estrogen receptors in breast cancer was suggestive (Rs = 0.309, 28 cases, P = 0.06). No correlation was found with other trace elements such as selenium, zinc and copper. These results seem neither to prove nor to disprove the role of cadmium in breast cancer initiation, promotion or progression.