Novel aspects in endocrine treatment of breast cancer

In recent years substantial improvements in the treatment of hormone responsive primary breast cancer have been achieved by the introduction of aromatase inhibitors (AIs). This demonstrates that withdrawal of estrogen might be superior to antagonism by the selective estrogen receptor modulator (SERM) tamoxifen. Increased efficacy of AIs could be explained by general inhibition of estrogen dependent mechanisms, not only those which are mediated by classical estrogen receptor (ER) that regulate tumor growth. Two variants of ER, α and ß have been described. There is evidence, that ERα regulates mechanisms in breast…