{"entity":{"id":"receptor-conversion-breast","kind":"term","name":"Receptor conversion: when the receptors change between the primary and a recurrence","aka":["receptor conversion","receptor discordance","receptor status change","ER conversion","HER2 conversion","retesting at recurrence","rebiopsy at relapse","biopsy of metastasis","discordance primary metastasis"],"tldr":"The receptors measured on the original tumour are not always the receptors of a cancer that comes back years later. On meta-analysis about a fifth of oestrogen receptor-positive primaries had become negative in their metastases, and about half had lost the progesterone receptor. It is why a returning cancer is biopsied again rather than treated from the old report.","summary":"A meta-analysis of 39 studies of paired primary tumours and distant metastases found conversion in both directions. From positive to negative the pooled rates were 22.5 percent for oestrogen receptor, 49.4 percent for progesterone receptor and 21.3 percent for HER2; from negative to positive they were 21.5 percent, 15.9 percent and 9.5 percent. The site mattered: oestrogen receptor discordance was significantly higher in central nervous system and bone metastases than in liver metastases, while progesterone receptor discordance was higher in bone and liver than in the brain. The authors' conclusion was that conversion happens often enough in the course of progression that reassessing receptor status in metastases is strongly encouraged, and that nobody has yet run the prospective study showing what treating on the new result rather than the old one does to survival (Schrijver 2018).\n\nBritish practice follows that logic cautiously. NICE CG81 recommendation 1.4.1 says that for people whose breast cancer has recurred, consider reassessing hormone receptor and HER2 status if a change in receptor status will lead to a change in management. The condition in that sentence is doing real work: a biopsy of a bone or liver deposit is not a trivial procedure, and it is worth it when the answer could open or close a treatment route, which in 2026 it increasingly can, because HER2-low and ultralow scoring decides eligibility for trastuzumab deruxtecan and because expression varies between blocks of the same tumour as well as between the primary and its metastases.\n\nSome of the apparent conversion is not the cancer changing. Immunohistochemistry has real limits at the bottom of its range, decalcified bone specimens stain badly, the cut-off for positivity moved from 10 percent to 1 percent internationally in 2010 and some countries moved later, and tumours are heterogeneous, so a single block may not represent the whole deposit. The safe reading is that the receptors are a property of the tissue tested on the day it was tested, not a permanent label on the patient.","asOf":"2026-09-25","links":[{"label":"Schrijver et al., Journal of the National Cancer Institute 2018: receptor conversion in distant breast cancer metastases, a systematic review and meta-analysis of 39 studies","url":"https://doi.org/10.1093/jnci/djx273"},{"label":"NICE CG81: advanced breast cancer, diagnosis and treatment, diagnosis and assessment section (published 23 February 2009, last updated 30 June 2026)","url":"https://www.nice.org.uk/guidance/cg81/chapter/Diagnosis-and-assessment"},{"label":"Royal College of Pathologists G148: dataset for histopathological reporting of breast disease in surgical excision specimens of breast cancer, version 3, November 2024 (full review due November 2026)","url":"https://www.rcpath.org/resourceLibrary/g148-dataset-for-histopathological-reporting-of-breast-disease-in-surgical-excision-specimens-of-breast-cancer.html"}],"tags":[],"related":["her2-low","endocrine-resistance","core-needle-biopsy","esr1-mutation"],"cancers":["breast-cancer","breast-hr-positive","breast-her2-positive","tnbc","her2-low-metastatic-breast-cancer","hr-positive-metastatic-post-cdk46"],"sections":["diagnostics"],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["er-pr-scoring-breast","her2-testing-uk-breast","er-pr-negative-threshold","her2-low","endocrine-resistance","esr1-mutation"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Biomarkers"},"route":"/terms/receptor-conversion-breast/","neighbours":{"term":[{"id":"core-needle-biopsy","kind":"term","name":"Core needle biopsy and fine-needle aspiration (FNA)","route":"/terms/core-needle-biopsy/"},{"id":"endocrine-resistance","kind":"term","name":"Endocrine resistance","route":"/terms/endocrine-resistance/"},{"id":"er-pr-negative-threshold","kind":"term","name":"ER and PR negative under 1 percent (the triple-negative threshold, and ER-low)","route":"/terms/er-pr-negative-threshold/"},{"id":"esr1-mutation","kind":"term","name":"ESR1 mutation","route":"/terms/esr1-mutation/"},{"id":"her2-testing-uk-breast","kind":"term","name":"HER2 testing in the UK: reflex ISH, the ratio against the copy number, and where the UK differs from ASCO/CAP","route":"/terms/her2-testing-uk-breast/"},{"id":"her2-low","kind":"term","name":"HER2-low and HER2-ultralow","route":"/terms/her2-low/"},{"id":"her2-positive","kind":"term","name":"HER2-positive (IHC 3+ or ISH-amplified)","route":"/terms/her2-positive/"},{"id":"hormone-receptor-status","kind":"term","name":"Hormone receptor status (ER / PR)","route":"/terms/hormone-receptor-status/"},{"id":"er-pr-scoring-breast","kind":"term","name":"How ER and PR are scored on a breast report (Allred score, H score, and why PR is not a UK core item)","route":"/terms/er-pr-scoring-breast/"}],"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"her2-low-metastatic-breast-cancer","kind":"cancer","name":"HER2-low and HER2-ultralow metastatic breast cancer","route":"/cancers/her2-low-metastatic-breast-cancer/"},{"id":"breast-her2-positive","kind":"cancer","name":"HER2-positive breast cancer","route":"/cancers/breast-her2-positive/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"hr-positive-metastatic-post-cdk46","kind":"cancer","name":"HR-positive metastatic breast cancer after CDK4/6 inhibitors","route":"/cancers/hr-positive-metastatic-post-cdk46/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"section":[{"id":"diagnostics","kind":"section","name":"Diagnostics & Biomarkers","route":"/fronts/diagnostics/"}]}}