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The enzyme that turns androgens into oestrogen in fat, muscle and breast tissue after the menopause. Aromatase inhibitors remove the oestrogen that drives most breast cancers in post-menopausal women.
Aromatase, the product of the CYP19A1 gene, converts androstenedione and testosterone into oestrone and oestradiol. After the menopause the ovaries stop making oestrogen and aromatase in peripheral fat, muscle and the breast itself becomes the main source, so inhibiting it with letrozole, anastrozole or exemestane lowers circulating oestrogen to very low levels and deprives hormone receptor-positive breast cancer of its growth signal. Aromatase inhibitors are the standard endocrine partner for CDK4/6 inhibitors in advanced disease and a standard adjuvant treatment in early disease; joint pain and bone loss are their characteristic side effects.
In plain words · The enzyme that turns androgens into oestrogen in fat, muscle and breast tissue after the menopause. Aromatase inhibitors remove the oestrogen that drives most breast cancers in post-menopausal women.
The enzyme that turns androgens into oestrogen in fat, muscle and breast tissue after the menopause. Aromatase inhibitors remove the oestrogen that drives most breast cancers in post-menopausal women.
Cytochrome P450 enzyme that aromatises the A ring of androgens to form oestrogens; expressed in adipose tissue, muscle, bone, brain and breast tumour stroma.
3 products aim at Aromatase (CYP19A1): small molecules and hormonal therapies. Inhibitors are shaped to fit the enzyme's active site so the reaction the cancer relies on stops.
Tumour-associated overexpression: HPA finds the RNA cancer enhanced in cancer (Glioblastoma Multiforme (TCGA)) and tissue enriched in normal placenta, so the tumour and the normal tissue it comes from share the target and the medicine relies on the difference in level. HPA CYP19A1: RNA tissue enriched (placenta 117 nTPM); high antibody staining in 1 normal tissue. Distribution: 1 cancer family in the corpus carries a prevalence row, label threshold or catalogue link for it (Breast cancer (all types)); approvals of single-target medicines aimed at it also list Ovarian cancer, Endometrial cancer, not counted; Open Targets associates it with 2 specific cancer types at or above 0.5 (breast cancer, breast carcinoma); the corpus evidence decides and the Open Targets list is quoted for comparison. (Rule 7 of scripts/fetch-target-specificity.ts.)
Sources: Human Protein Atlas CYP19A1 tissue; Human Protein Atlas CYP19A1 pathology; Open Targets ENSG00000137869 associations
First described 1986. Earliest sequence paper UniProt cites for the protein: Evans C.T. et al, Proc. Natl. Acad. Sci. U.S.A, 1986, "Isolation and characterization of a complementary DNA specific for human aromatase-system cytochrome P-450 mRNA". Source.
Cytochrome P450 enzyme that aromatises the A ring of androgens to form oestrogens; expressed in adipose tissue, muscle, bone, brain and breast tumour stroma.
RNA: tissue enriched (placenta 117 nTPM), detected in many normal tissues.
RNA cancer enhanced: Glioblastoma Multiforme 3 pTPM.
No cancer sample stained medium or high.
HPA CYP19A1 tissue · HPA CYP19A1 pathology · HPA protein class: FDA approved drug targets
Human Protein Atlas version 25.1, antibody staining at reliability approved, enhanced or supported; used under CC BY-SA 3.0. Staining counts are patients per level in the atlas cohort, not population prevalence.
| Cancer | Prevalence | Measure | Note | Source |
|---|---|---|---|---|
| HR-positive / HER2-negative breast cancer | about 70% | Share of breast cancers that are hormone receptor-positive, the population aromatase inhibitors treat | cancer.org |
Approximate, population-level figures; the measure column says what was counted. Ranges show the midpoint as a bar.
Aminoglutethimide produced a medical adrenalectomy for advanced breast and prostate cancer in the 1970s and 1980s, the ancestor of today's aromatase inhibitors, and was withdrawn once selective drugs arrived.
Anastrozole is a daily tablet that stops the body making oestrogen after the menopause. It treats and prevents hormone-receptor-positive breast cancer and is an alternative to tamoxifen after surgery for ductal carcinoma in situ.
Formestane, launched in Europe in 1993, was the first selective aromatase inhibitor for advanced breast cancer, given by injection every two weeks; oral exemestane and the non-steroidal inhibitors made it redundant within a few years.
Query for this target: (TITLE:"Aromatase" OR ABSTRACT:"Aromatase" OR TITLE:"CYP19A1" OR ABSTRACT:"CYP19A1") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Aromatase (CYP19A1), not a curated reading list.
Shares Anastrozole, Exemestane, Letrozole (and other aromatase inhibitors), HR-positive / HER2-negative breast cancer.
Shares Anastrozole, Exemestane, Letrozole (and other aromatase inhibitors).
Shares Exemestane, Letrozole (and other aromatase inhibitors), HR-positive / HER2-negative breast cancer.
Shares Anastrozole, HR-positive / HER2-negative breast cancer.
Shares Letrozole (and other aromatase inhibitors), HR-positive / HER2-negative breast cancer.
Shares Exemestane, Letrozole (and other aromatase inhibitors).
Shares Exemestane, HR-positive / HER2-negative breast cancer.
Shares Exemestane, Letrozole (and other aromatase inhibitors), HR-positive / HER2-negative breast cancer.