A report on Tamoxifen

Nolvadex (tamoxifen) 20 mg tablets.
Crystallographic structure of afimoxifene (carbon = white, oxygen = red, nitrogen = blue) complexed with ligand binding domain of estrogen receptor alpha (ERα) (cyan ribbon).

Selective estrogen receptor modulator used to prevent breast cancer in women and treat breast cancer in women and men.

- Tamoxifen
Nolvadex (tamoxifen) 20 mg tablets.

48 related topics with Alpha

Overall
Tamoxifen, a nonsteroidal triphenylethylene antiestrogen and a widely used drug in the treatment of breast cancer.

Selective estrogen receptor modulator

16 links

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).

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).

Tamoxifen, a nonsteroidal triphenylethylene antiestrogen and a widely used drug in the treatment of breast cancer.
Figure 2: Nolvadex (tamoxifen) 20-milligram tablets (UK)
Figure 3: The domain structures of ERα and ERβ, including some of the known phosphorylation sites involved in ligand-independent regulation.
Figure 4: Structural basis for the mechanism of estrogen receptor agonist and antagonist action. The structures shown here are of the ligand binding domain (LBD) of the estrogen receptor (green cartoon diagram) complexed with either the agonist diethylstilbestrol (top, ) or antagonist 4-hydroxytamoxifen (bottom, ). The ligands are depicted as space filling spheres (white = carbon, red = oxygen). When an agonist is bound to a nuclear receptor, the C-terminal alpha helix of the LBD (H12; light blue) is positioned such that a coactivator protein (red) can bind to the surface of the LBD. Shown here is just a small part of the coactivator protein, the so-called NR box containing the LXXLL amino acid sequence motif. Antagonists occupy the same ligand binding cavity of the nuclear receptor. However antagonist ligands in addition have a sidechain extension which sterically displaces H12 to occupy roughly the same position in space as coactivators bind. Hence coactivator binding to the LBD is blocked.
Figure 5: 4-hydroxytamoxifen (red) overlaid with 17β-estradiol (black)
Figure 6: Trans-form of clomifene with the triphenylethylene structure in red.
Figure 8: Chemical structure of toremifene
Figure 9: Raloxifene has a benzothiophene group (red) and is connected with a flexible carbonyl hinge to a phenyl 4-piperidinoethoxy side chain (green).
Figure 10: Chemical structure of nafoxidine with the dihydronapthalene group in red.
Figure 11: Chemical structure of lasofoxifene shows cis-oriented phenyls.
Figure 12: Bazedoxifene includes an indole system (red) which is connected to an amine through a benzyloxyethyl chain (green).
Figure 13: Chemical structure of ospemifene. Ethoxy side chain ends with a hydroxy group (red) instead of a dimethylamino group as with first-generation SERMs.
Figure 14: The ABCD steroid ring system in 17β-estradiol.
Figure 15: "A ring" (A) and "D ring" (D) marked in raloxifene.

Tamoxifen is a first-line hormonal treatment of ER-positive metastatic breast cancer.

Clomifene

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Medication used to treat infertility in women who do not ovulate, including those with polycystic ovary syndrome.

Medication used to treat infertility in women who do not ovulate, including those with polycystic ovary syndrome.

It has been found to be useful in the treatment of some cases of gynecomastia but it is not as effective as tamoxifen or raloxifene for this indication.

A bottle of raloxifene.

Raloxifene

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Medication used to prevent and treat osteoporosis in postmenopausal women and those on glucocorticoids.

Medication used to prevent and treat osteoporosis in postmenopausal women and those on glucocorticoids.

A bottle of raloxifene.

In the Study of Tamoxifen and Raloxifene (STAR) trial, 60 mg/day raloxifene was 78% as effective as 20 mg/day tamoxifen in preventing non-invasive breast cancer.

A dimer of the ligand-binding region of ERβ (PDB rendering based on ).

Estrogen receptor

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Estrogen receptors (ERs) are a group of proteins found inside cells.

Estrogen receptors (ERs) are a group of proteins found inside cells.

A dimer of the ligand-binding region of ERβ (PDB rendering based on ).
The domain structures of ERα and ERβ, including some of the known phosphorylation sites involved in ligand-independent regulation.
A dimer of the ligand-binding region of ERα (PDB rendering based on ).
Nolvadex (tamoxifen) 20 mg
Arimidex (anastrozole) 1 mg

Selective estrogen receptor modulators (e.g., tamoxifen, clomifene, raloxifene)

An illustration of breast cancer

Breast cancer

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Cancer that develops from breast tissue.

Cancer that develops from breast tissue.

An illustration of breast cancer
Breast cancer showing an inverted nipple, lump, and skin dimpling
Early signs of possible breast cancer
Tumor in the breast visualized by Breast-Computertomography (Breast-CT)
All types of alcoholic beverages, including beer, wine, or liquor, cause breast cancer.
Ducts and lobules, the main locations of breast cancers
Overview of signal transduction pathways involved in programmed cell death. Mutations leading to loss of this ability can lead to cancer formation.
Histopathologic types of breast cancer, with relative incidences and prognoses
A mobile breast cancer screening unit in New Zealand
Chest after right breast mastectomy
Internal radiotherapy for breast cancer
Breasts after double mastectomy followed by nipple-sparing reconstruction with implants
An extreme example of an advanced recurrent breast cancer with an ulcerating axillary mass
Breast cancer surgery in 18th century
Radical mastectomy, Halsted's surgical papers
The pink ribbon is a symbol to show support for breast cancer awareness.
MRI showing breast cancer
Excised human breast tissue, showing an irregular, dense, white stellate area of cancer 2cm in diameter, within yellow fatty tissue
High-grade invasive ductal carcinoma, with minimal tubule formation, marked pleomorphism, and prominent mitoses, 40x field
Micrograph showing a lymph node invaded by ductal breast carcinoma, with an extension of the tumor beyond the lymph node
Neuropilin-2 expression in normal breast and breast carcinoma tissue
F-18 FDG PET/CT: A breast cancer metastasis to the right scapula
Needle breast biopsy
Elastography shows stiff cancer tissue on ultrasound imaging.
Ultrasound image shows irregularly shaped mass of breast cancer.
Infiltrating (invasive) breast carcinoma
Mammograms showing a normal breast (left) and a breast with cancer (right)
Stage T1 breast cancer
Stage T2 breast cancer
Stage T3 breast cancer
Metastatic or stage 4 breast cancer
Stage 1A breast cancer
Stage 1B breast cancer
Stage 2A breast cancer
Stage 2A breast cancer
Stage 2B breast cancer
Stage 2B breast cancer
Stage 2B breast cancer
Stage 3A breast cancer
Stage 3A breast cancer
Stage 3A breast cancer
Stage 3B breast cancer
Stage 3B breast cancer
Stage 4 breast cancer

The medications tamoxifen or raloxifene may be used in an effort to prevent breast cancer in those who are at high risk of developing it.

The location and development of endometrial cancer.

Endometrial cancer

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Cancer that arises from the endometrium .

Cancer that arises from the endometrium .

The location and development of endometrial cancer.
The location and development of endometrial cancer.
The autosomal dominant inheritance pattern seen in Lynch syndrome
Immunohistochemistry of endometrial endometrioid carcinoma with wild-type pattern of p53 expression, with variable proportion of tumor cell nuclei staining with variable intensity.
Vaginal ultrasonography with an endometrial fluid accumulation (darker area) in a postmenopausal uterus, a finding that is highly suspicious for endometrial cancer
Polypoidal endometrial carcinoma
Relative incidences of endometrial carcinomas by histopathology.
Endometrioid endometrial adenocarcinoma—very high magnification—H&E stain
A keyhole hysterectomy, one possible surgery to treat endometrial cancer
alt=A diagram of stage IA and IB endometrial cancer|Stage IA and IB endometrial cancer
alt=A diagram of stage II endometrial cancer|Stage II endometrial cancer
alt=A diagram of stage III endometrial cancer|Stage III endometrial cancer
alt=A diagram of stage IV endometrial cancer|Stage IV endometrial cancer

Risk factors for endometrial cancer include obesity, insulin resistance and diabetes mellitus, breast cancer, use of tamoxifen, never having had a child, late menopause, high levels of estrogen, and increasing age.

Estrogen receptor alpha

8 links

One of two main types of estrogen receptor, a nuclear receptor that is activated by the sex hormone estrogen.

One of two main types of estrogen receptor, a nuclear receptor that is activated by the sex hormone estrogen.

Selective estrogen receptor modulators (e.g., tamoxifen, clomifene, raloxifene)

Fulvestrant, a steroidal antiestrogen and a drug used in the treatment of breast cancer.

Antiestrogen

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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.

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.

Fulvestrant, a steroidal antiestrogen and a drug used in the treatment of breast cancer.

Antiestrogens include selective estrogen receptor modulators (SERMs) like tamoxifen, clomifene, and raloxifene, the ER silent antagonist and selective estrogen receptor degrader (SERD) fulvestrant, aromatase inhibitors (AIs) like anastrozole, and antigonadotropins including androgens/anabolic steroids, progestogens, and GnRH analogues.

Triphenylethylene

9 links

Simple aromatic hydrocarbon that possesses weak estrogenic activity.

Simple aromatic hydrocarbon that possesses weak estrogenic activity.

For comparison, the relative binding affinities of derivatives of triphenylethylene were 1.6% for tamoxifen, 175% for afimoxifene (4-hydroxytamoxifen), 15% for droloxifene, 1.4% for toremifene (4-chlorotamoxifen), 0.72% for clomifene, and 0.72% for nafoxidine.

Hypothalamic–pituitary–gonadal axis in females, with estrogen exerting mainly negative feedback on follicle-stimulating hormone secretion from the pituitary gland.

Ovulation induction

4 links

Stimulation of ovulation by medication.

Stimulation of ovulation by medication.

Hypothalamic–pituitary–gonadal axis in females, with estrogen exerting mainly negative feedback on follicle-stimulating hormone secretion from the pituitary gland.
Pregnancy rates in ovulation induction when using antiestrogens, as functions of the size of the leading follicle as measured by transvaginal ultrasonography at days 11 - 13 (bottom scale), as well as the thickness of the endometrial lining (4 different curves).

Antiestrogen, causing an inhibition of the negative feedback of estrogen on the pituitary gland, resulting in an increase in secretion of follicle-stimulating hormone. Medications in use for this effect are mainly clomifene citrate and tamoxifen (both being selective estrogen-receptor modulators), as well as letrozole (an aromatase inhibitor.