Association between Urine Cadmium and Breast Cancer Risk According to Estrogen Receptor and Human Epidermal Growth Factor Receptor 2

Association between Urine Cadmium and Breast Cancer Risk According to Estrogen Receptor and Human Epidermal Growth Factor Receptor 2Abstract Number:1495 Loreta Strumylaite*, Rima Kregzdyte, Algirdas Bogusevicius, Lina Poskiene, Dale Baranauskiene, and Darius Pranys Loreta Strumylaite* Lithuanian University of Health Sciences, Lithuania, E-mail Address: [email protected] , Rima Kregzdyte Lithuanian University of Health Sciences, Lithuania, E-mail Address: [email protected] , Algirdas Bogusevicius Lithuanian University of Health Sciences, Lithuania, E-mail Address: [email protected] , Lina Poskiene Lithuanian University of Health Sciences, Lithuania, E-mail Address: [email protected] , Dale Baranauskiene Lithuanian University of Health Sciences, Lithuania, E-mail Address: [email protected] , and Darius Pranys Lithuanian University of Health Sciences, Lithuania, E-mail Address: [email protected] AbstractThere is evidence that cadmium may contribute to the cause of breast cancer acting as metalloestrogens via estrogen receptor (ER) and/or directly transforming normal human breast epithelial cells into a basal-like cancer phenotype characterized by negative human epidermal growth factor receptor 2 (HER2). We examined the role of urinary cadmium, i.e. long-term exposure biomarker, as a potential breast cancer risk factor for women using data from a hospital-based case-control study. Information on possible risk factors was collected from 585 cases and 1170 controls via a structured questionnaire. Urinary cadmium was determined by atomic absorption spectrometry. The ER and HER2 levels in tumor tissue were analyzed by immunohistochemistry. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for breast cancer by creatinine-adjusted urinary cadmium. Statistical tests were two-sided. Women with greater creatinine-adjusted urine cadmium (3rd quartile: 0.241–0.399 µg/g and 4th quartile: = 0.4 µg/g) experienced 1.6 times higher risk of breast cancer compared with those having cadmium concentration lower than 0.147 µg/g (1st quartile) (OR = 1.6; 95% CI = 1.19–2.17 and OR = 1.62; 95% CI = 1.19–2.21, respectively, p trend = 0.001) after adjustment for age and other confounders. Both ER+ and HER2- cases from the highest quartile of urine cadmium exhibited approximately twice the breast cancer risk of those in the lowest quartile (OR = 1.9; 95% CI = 1.31–2.74 and OR = 1.87; 95% CI = 1.33–2.62, respectively, p trend < 0.001) after adjustment for confounders. The data support cadmium as a risk factor for breast cancer, especially for both ER+ and HER2- cancer patients.