tumor is a tumor which consists of cells that express receptors for certain hormones. The term most commonly refers to estrogen receptor
positive tumors (i.e. tumors that contain estrogen receptor positive cells), but can also include progesterone receptor
positive tumors. Estrogen-receptor-positive tumors depend on the presence of estrogen for ongoing proliferation
. There are two ways for treating these kind of tumors:
- Lowering systemic levels of estrogen, achieved by the use of drugs from the aromatase inhibitor category. These drugs target one of the enzymes that takes part in the biosynthesis of estrogen.
- Blockage of the estrogen receptors on the cancerous cells, thus preventing estrogen binding, leading to decreased proliferation. Drugs in this category are also referred to as SERMs (Selective estrogen receptor modulator) since they are able to block estrogen receptors in a selective manner.