A report on Aromatase inhibitor

Anastrozole, a non steroidal aromatase inhibitor and a widely used drug in the treatment of breast cancer.
Often used as a cancer treatment in postmenopausal women, AIs work by blocking the conversion of androstenedione and testosterone into estrone and estradiol, respectively, which are both crucial to the growth of developing breast cancers (AIs are also effective at treating ovarian cancer, but less commonly so). In the diagram, the adrenal gland (1) releases androstenedione (3) while the ovaries (2) secrete testosterone (4). Both hormones travel to peripheral tissues or a breast cell (5), where they would be converted into estrone (8) or estradiol (9) if not for AIs (7), which prevent the enzyme CYP19A1 (also known as aromatase or estrogen synthase) (6) from catalyzing the reaction that turns androstenedione and testosterone into estrone and estradiol. In the diagram, Part A represents the successful conversion of androstenedione and testosterone into estrone and estradiol in the liver. Part B represents the blockage of this conversion by aromatase inhibitors both in peripheral tissues and in the breast tumor itself.
Arimidex (anastrozole) 1 mg tablets

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.

- Aromatase inhibitor
Anastrozole, a non steroidal aromatase inhibitor and a widely used drug in the treatment of breast cancer.

23 related topics with Alpha

Overall

Anastrozole

5 links

Medication used in addition to other treatments for breast cancer.

Medication used in addition to other treatments for breast cancer.

Anastrozole is in the aromatase-inhibiting family of medications.

An illustration of breast cancer

Breast cancer

5 links

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

Aromatase inhibitors (such as exemestane and anasatrozole) may be more effective than selective estrogen receptor modulators (such as tamoxifen) at reducing breast cancer risk and they are not associated with an increased risk of endometrial cancer and thromboembolism.

Nolvadex (tamoxifen) 20 mg tablets.

Tamoxifen

5 links

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

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

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).

The aromatase inhibitor aminoglutethimide induces the metabolism of tamoxifen.

Femara 2.5 mg oral tablet

Letrozole

4 links

Femara 2.5 mg oral tablet

Letrozole, sold under the brand name Femara among others, is an aromatase inhibitor which is used in the treatment of hormonally-responsive breast cancer after surgery.

Adult male with significant gynecomastia

Gynecomastia

3 links

Abnormal non-cancerous enlargement of one or both breasts in males due to the growth of breast tissue as a result of a hormone imbalance between estrogen and androgen.

Abnormal non-cancerous enlargement of one or both breasts in males due to the growth of breast tissue as a result of a hormone imbalance between estrogen and androgen.

Adult male with significant gynecomastia
Gynecomastia of boys going through puberty.
An exceptional case of extreme gynecomastia in a 63-year-old man, treated with the nonsteroidal antiandrogen flutamide for prostate cancer. (a) With flutamide; (b) after discontinuation of flutamide. More than 90% of cases of gynecomastia with nonsteroidal antiandrogens including flutamide are mild to moderate.
Pathology: A large glandular mass of male breast tissue, surgically removed
Microscopic image showing gynecomastoid hyperplasia, the cellular changes seen in gynecomastia H&E stain
Male with asymmetrical gynecomastia, before and after excision of the gland and liposuction of the waist

Medications such as aromatase inhibitors have been found to be effective and even in rare cases of gynecomastia from disorders such as aromatase excess syndrome or Peutz–Jeghers syndrome, but surgical removal of the excess tissue can be needed to correct the condition.

Aromatase

5 links

Enzyme responsible for a key step in the biosynthesis of estrogens.

Enzyme responsible for a key step in the biosynthesis of estrogens.

Aromatase inhibitors, which stop the production of estrogen in postmenopausal women, have become useful in the management of patients with breast cancer whose lesion was found to be estrogen receptor positive.

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

Estrogen receptor

5 links

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

Endocrine therapy for breast cancer involves selective estrogen receptor modulators (SERMS), such as tamoxifen, which behave as ER antagonists in breast tissue, or aromatase inhibitors, such as anastrozole.

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

Ovulation induction

2 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.

4-Androstenedione for comparison

Exemestane

1 links

Medication used to treat breast cancer.

Medication used to treat breast cancer.

4-Androstenedione for comparison

It is a member of the class of antiestrogens known as aromatase inhibitors.

Testolactone

0 links

Testolactone (INN, USAN) (brand name Teslac) is a non-selective, irreversible, steroidal aromatase inhibitor which is used as an antineoplastic drug to treat advanced-stage breast cancer.