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PR status is read the same way as ER: 1 percent or more of nuclei staining is positive. It is measured alongside ER, adds to prognosis, and a tumour positive for either receptor counts as hormone-receptor-positive.
The ASCO/CAP 2020 guideline applies the same 1 percent nuclear staining threshold to the progesterone receptor as to ER; PR is a downstream target of ER signalling, so PR-negativity in an ER-positive tumour flags a less endocrine-responsive cancer with a worse outlook. Labels use the phrase 'hormone receptor (HR)-positive', which by convention means ER-positive or PR-positive or both, so PR alone can qualify a patient for endocrine therapy and CDK4/6 inhibitors. In endometrial cancer PR expression is used to select progestin therapy under guidelines rather than labels.
In plain words · 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.
A PR-positive result adds to the case for hormone-blocking treatment and generally means a better outlook; a PR-negative result in an ER-positive cancer is a sign the cancer may respond less well to hormone therapy alone. Either receptor at 1 percent or more makes the cancer hormone-receptor-positive for treatment purposes.
Written only from the label or guideline text cited on this page. Not medical advice; your own report and the reading your team gives it come first.
PR-positive: at least 1 percent of tumour cell nuclei stain positive by IHC; PR-negative below 1 percent.
“PgR-positive... if ≥ 1% of tumor cell nuclei are immunoreactive”
ASCO/CAP estrogen and progesterone receptor testing guideline, 2020 update (Allison et al., J Clin Oncol)| Threshold | Drug | Cancer | Regulator | Source |
|---|---|---|---|---|
| Hormone receptor-positive (ER or PR >= 1%) Palbociclib label wording; the 1 percent rule is the ASCO/CAP guideline's, not the label's. | Palbociclib | HR-positive / HER2-negative breast cancer | FDA | label |
Also defined by ASCO/CAP estrogen and progesterone receptor testing guideline, 2020 update (Allison et al., J Clin Oncol).
Matched on the name and aliases of the readout in the title, setting and summary of each trial; a match is a mention, not proof the readout was an entry criterion.
Shares ER status (oestrogen receptor by IHC), HR-positive / HER2-negative breast cancer and the tags biomarker, hormone-receptor.
Shares Immunohistochemistry (IHC), Breast cancer (all types), HR-positive / HER2-negative breast cancer and the tag biomarker.
Shares Immunohistochemistry (IHC), Breast cancer (all types), HR-positive / HER2-negative breast cancer and the tag biomarker.
Shares Immunohistochemistry (IHC), Endometrial cancer and the tag biomarker.
Shares Immunohistochemistry (IHC), Breast cancer (all types), HR-positive / HER2-negative breast cancer and the tag biomarker.
Shares Immunohistochemistry (IHC), Endometrial cancer, HR-positive / HER2-negative breast cancer and the tag biomarker.
Shares Ki-67 index (proliferation by IHC) and the tag biomarker.
Shares Endometrial cancer, HR-positive / HER2-negative breast cancer and the tag biomarker.