Selective estrogen receptor modulators (SERMs), also known as estrogen receptor agonist/antagonists (ERAAs), are a class of drugs that act on the estrogen receptor (ER). A characteristic that distinguishes these substances from pure ER agonists and antagonists is that their action is different in various tissues, thereby granting the possibility to selectively inhibit or stimulate estrogen-like action in various tissues.
Tamoxifen, sold under the brand name Nolvadex among others, is a selective estrogen receptor modulator used to prevent breast cancer in women and men. It is also being studied for other types of cancer. It has been used for Albright syndrome. Tamoxifen is typically taken daily by mouth for five years for breast cancer.
Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and in men, and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when supplementing testosterone exogenously. They may also be used for chemoprevention in women at high risk for breast cancer.
Estrogen receptors (ERs) are a group of proteins found inside cells. They are receptors that are activated by the hormone estrogen (17β-estradiol). Two classes of ER exist: nuclear estrogen receptors, which are members of the nuclear receptor family of intracellular receptors, and membrane estrogen receptors (mERs), which are mostly G protein-coupled receptors. This article refers to the former (ER).
Exemestane, sold under the brand name Aromasin among others, is a medication used to treat breast cancer. It is a member of the class of antiestrogens known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers have estrogen receptors (ERs), and are called ER-positive. They may also be called estrogen-responsive, hormonally-responsive, or hormone-receptor-positive. Aromatase is an enzyme that synthesizes estrogen. Aromatase inhibitors block the synthesis of estrogen. This lowers the estrogen level, and slows the growth of cancers.
Toremifene, sold under the brand name Fareston among others, is a medication which is used in the treatment of advanced breast cancer in postmenopausal women. It is taken by mouth.
CYP27A1 is a gene encoding a cytochrome P450 oxidase, and is commonly known as sterol 27-hydroxylase. This enzyme is located in many different tissues where it is found within the mitochondria. It is most prominently involved in the biosynthesis of bile acids.
The sigma-2 receptor (σ2R) is a sigma receptor subtype that has attracted attention due to its involvement in diseases such as neurological diseases, neurodegenerative, neuro-opthamalic and cancer. It is currently under investigation for its potential diagnostic and therapeutic uses.
Triple-negative breast cancer (TNBC) is any breast cancer that either lacks or shows low levels of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) overexpression and/or gene amplification. Triple-negative is sometimes used as a surrogate term for basal-like.
Selective androgen receptor modulators (SARMs) are a class of drugs that were developed with the intention of maintaining some of the desirable effects of androgens, such as improving bone density and increasing lean body mass, with a much lower risk of androgenic side effects than alternative therapies such as testosterone.
Antiestrogens, also known as estrogen antagonists or estrogen blockers, are a class of drugs which prevent estrogens like estradiol from mediating their biological effects in the body. They act by blocking the estrogen receptor (ER) and/or inhibiting or suppressing estrogen production. Antiestrogens are one of three types of sex hormone antagonists, the others being antiandrogens and antiprogestogens. Antiestrogens are commonly used to stop steroid hormones, estrogen, from binding to the estrogen receptors leading to the decrease of estrogen levels. Decreased levels of estrogen can lead to complications in sexual development. Antiandrogens are sex hormone antagonists which are able to lower the production and the effects that testosterone can have on female bodies.
Antihormone therapy is a type of hormone therapy that suppresses selected hormones or their effects, in contrast with hormone replacement therapy, which encourages hormone activity.
A hormone-receptor-positive (HR+) tumor is a tumor which consists of cells that express receptors for certain hormones. The term most commonly refers to estrogen receptor positive tumors, but can also include progesterone receptor positive tumors. Estrogen-receptor-positive tumors depend on the presence of estrogen for ongoing proliferation.
Breast cancer classification divides breast cancer into categories according to different schemes criteria and serving a different purpose. The major categories are the histopathological type, the grade of the tumor, the stage of the tumor, and the expression of proteins and genes. As knowledge of cancer cell biology develops these classifications are updated.
A selective estrogen receptor degrader or downregulator (SERD) is a type of drug which binds to the estrogen receptor (ER) and, in the process of doing so, causes the ER to be degraded and thus downregulated. They are used to treat estrogen receptor-sensitive or progesterone receptor-sensitive breast cancer, along with older classes of drugs like selective estrogen receptor modulators (SERMs) and aromatase inhibitors.
Ethamoxytriphetol is a synthetic nonsteroidal antiestrogen that was studied clinically in the late 1950s and early 1960s but was never marketed. MER-25 was first reported in 1958, and was the first antiestrogen to be discovered. It has been described as "essentially devoid of estrogenic activity" and as having "very low estrogenic activity in all species tested". However, some estrogenic effects in the uterus have been observed, so it is not a pure antiestrogen but is, instead, technically a selective estrogen receptor modulator (SERM). For all intents and purposes, it is a nearly pure antiestrogen, however.
A steroidogenesis inhibitor, also known as a steroid biosynthesis inhibitor, is a type of drug which inhibits one or more of the enzymes that are involved in the process of steroidogenesis, the biosynthesis of endogenous steroids and steroid hormones. They may inhibit the production of cholesterol and other sterols, sex steroids such as androgens, estrogens, and progestogens, corticosteroids such as glucocorticoids and mineralocorticoids, and neurosteroids. They are used in the treatment of a variety of medical conditions that depend on endogenous steroids.
Elacestrant, sold under the brand name Orserdu, is an anticancer medication which is used in the treatment of breast cancer. It is taken by mouth.
Estrogen deprivation therapy, also known as endocrine therapy, is a form of hormone therapy that is used in the treatment of breast cancer. Modalities include antiestrogens or estrogen blockers such as selective estrogen receptor modulators (SERMs) like tamoxifen, selective estrogen receptor degraders like fulvestrant, and aromatase inhibitors like anastrozole and ovariectomy.
Endocrine therapy is a common treatment for estrogen receptor positive breast cancer. However, resistance to this therapy can develop, leading to relapse and progression of disease. This highlights the need for new strategies to combat this resistance.
