# Progesterone receptor (PGR)

Source: https://onco.cc/targets/pgr/  
OnCo record `pgr` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The progesterone receptor is the hormone receptor that, alongside the oestrogen receptor, marks breast cancers likely to respond to hormone therapy, and it is the target of the progestins megestrol and medroxyprogesterone used in endometrial and breast cancer.

## Summary

The progesterone receptor (PR, gene PGR) is a nuclear receptor whose expression is switched on by oestrogen signalling, so PR positivity in a breast cancer indicates an intact, functioning oestrogen receptor pathway and a better response to endocrine therapy; it is reported with ER and HER2 on every breast cancer pathology report. Progestins such as megestrol acetate and medroxyprogesterone act through the receptor and are used as hormonal treatment for advanced endometrial cancer and as later-line therapy in hormone receptor-positive breast cancer, and progestin-containing intrauterine systems are used for fertility-sparing treatment of early endometrial cancer.

## Fields

- Kind: Target
- Last checked: 2026-09-04
- Symbol: PGR
- Class: nuclear-receptor
- Biology: PGR encodes two isoforms, PR-A and PR-B, from alternative promoters; the receptor binds progesterone, dimerises and regulates transcription at progesterone response elements, and it cross-talks with the oestrogen receptor at shared chromatin sites. In breast cancer PR expression is a marker of ER activity and of luminal A biology; loss of PR in an ER-positive tumour predicts a poorer response to endocrine therapy. In the endometrium progesterone opposes oestrogen-driven proliferation, which is why unopposed oestrogen causes endometrial cancer and progestins treat it.
- Where found: Breast epithelium and most ER-positive breast cancers; Endometrium and endometrial cancers; Ovary, uterus and brain

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Progesterone_receptor
- UniProt P06401: PGR: https://www.uniprot.org/uniprotkb/P06401/entry
- HGNC:8910 PGR: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:8910

## Connected records

- targets: [Estrogen receptor (ERα)](https://onco.cc/targets/estrogen-receptor/)
- biomarkers: [PR status (progesterone receptor by IHC)](https://onco.cc/biomarkers/pr-status/)
- cancers: [Endometrial cancer](https://onco.cc/cancers/endometrial/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/)
- drugs: [Megestrol acetate](https://onco.cc/drugs/megestrol/), [Progestins (megestrol acetate, medroxyprogesterone, levonorgestrel IUD)](https://onco.cc/drugs/megestrol-progestins/)
- terms: [Immunohistochemistry (IHC)](https://onco.cc/terms/ihc/)

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JSON: https://onco.cc/api/v1/entities/pgr.json