Estrogen-dependent Breast Cancer and Sodium-dependent Organic Anion Transporter

Breast cancer in women is the most prevalent type of cancer and 95% of these cancers are hormone-dependent. Although the plasma levels of active estrogen in postmenopausal women is depend on the concentration of biological effects, the two-thirds of estrogen-dependent breast cancers are emerging in this period. By contrast, inactive estrogen sulphated steroids are still present in the plasma in micromolar concentrations. Intratumoral production of hormonally-active estrogens from sulphated steroids plays an important role in the proliferation of breast cancer cells, especially in postmenopausal women. Sulphated steroids require a membrane transporter to be carried into the cell because of their hydrophilic structure. To date, the answer of how sulphated steroids are carried into the cell still remains unclear. Therefore, the aim of this review was to determine the role of SOAT (Sodium-dependent Organic Anion Transporter), as a new member of the SLC-family, for the estrogen-dependent proliferation of breast cancer.