{"entity":{"id":"pr-status","kind":"biomarker","name":"PR status (progesterone receptor by IHC)","aka":["PR status","PR-positive","PR positive","PR+","PgR","progesterone receptor status","PR-negative","PR >= 1%"],"tldr":"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.","summary":"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.","asOf":"2026-09-23","links":[{"label":"ASCO/CAP estrogen and progesterone receptor testing guideline, 2020 update (Allison et al., J Clin Oncol)","url":"https://doi.org/10.1200/JCO.19.02309"}],"tags":["biomarker","hormone-receptor"],"related":["er-status","ki-67-index"],"cancers":["breast-hr-positive","breast-cancer","endometrial"],"sections":[],"technologies":[],"targets":[],"drugs":["tamoxifen","letrozole","fulvestrant","palbociclib"],"companies":[],"institutions":[],"pathways":[],"terms":["hormone-receptor-status","ihc"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"target":"pgr","measurement":"ihc-score","scoringRule":{"text":"PR-positive: at least 1 percent of tumour cell nuclei stain positive by IHC; PR-negative below 1 percent.","quote":"PgR-positive... if ≥ 1% of tumor cell nuclei are immunoreactive","source":"https://doi.org/10.1200/JCO.19.02309","sourceLabel":"ASCO/CAP estrogen and progesterone receptor testing guideline, 2020 update (Allison et al., J Clin Oncol)"},"thresholds":[{"value":"Hormone receptor-positive (ER or PR >= 1%)","drugId":"palbociclib","cancerId":"breast-hr-positive","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=89a142d5-7e61-48bf-9e77-e2cd124c4792","quote":"hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer","status":"current","note":"Palbociclib label wording; the 1 percent rule is the ASCO/CAP guideline's, not the label's."}],"definedBy":{"label":"ASCO/CAP estrogen and progesterone receptor testing guideline, 2020 update (Allison et al., J Clin Oncol)","url":"https://doi.org/10.1200/JCO.19.02309"},"tests":[],"assays":[],"companionDiagnostics":[],"forPatient":"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."},"route":"/biomarkers/pr-status/","neighbours":{"biomarker":[{"id":"er-status","kind":"biomarker","name":"ER status (oestrogen receptor by IHC)","route":"/biomarkers/er-status/"},{"id":"ki-67-index","kind":"biomarker","name":"Ki-67 index (proliferation by IHC)","route":"/biomarkers/ki-67-index/"}],"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"endometrial","kind":"cancer","name":"Endometrial cancer","route":"/cancers/endometrial/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"}],"drug":[{"id":"fulvestrant","kind":"drug","name":"Fulvestrant","route":"/drugs/fulvestrant/"},{"id":"letrozole","kind":"drug","name":"Letrozole (and other aromatase inhibitors)","route":"/drugs/letrozole/"},{"id":"palbociclib","kind":"drug","name":"Palbociclib","route":"/drugs/palbociclib/"},{"id":"tamoxifen","kind":"drug","name":"Tamoxifen","route":"/drugs/tamoxifen/"}],"term":[{"id":"hormone-receptor-status","kind":"term","name":"Hormone receptor status (ER / PR)","route":"/terms/hormone-receptor-status/"},{"id":"ihc","kind":"term","name":"Immunohistochemistry (IHC)","route":"/terms/ihc/"}],"target":[{"id":"pgr","kind":"target","name":"Progesterone receptor (PGR)","route":"/targets/pgr/"}]}}