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Prospective Validation of a 21-Gene Expression Assay in Breast Cancer
Sparano JA, Gray RJ, Makower DF, Pritchard KI, et al. (2015). New England Journal of Medicine. PubMed 26412349 · DOI 10.1056/NEJMoa1510764 · PubMed record
What kind of source: Prospective trial (TAILORx), low-score arm. Where it sits in the summary: Established. Back to the summary
What it says, in plain language
In TAILORx, women with hormone-receptor-positive, HER2-negative, node-negative breast cancer and a score of 0 to 10 received endocrine therapy alone. Five years later, distant recurrence was rare. The paper also states how the test is done: on tumor tissue fixed in paraffin, in a central laboratory.
Source access: the full text was read as a PubMed Central author manuscript. It is linked rather than reproduced because redistribution is not permitted for this copy. Open the PubMed record and follow its PMC link.
The exact words we relied on
“At 5 years, in this patient population, the rate of invasive disease-free survival was 93.8% (95% confidence interval [CI], 92.4 to 94.9), the rate of freedom from recurrence of breast cancer at a distant site was 99.3% (95% CI, 98.7 to 99.6)” — PMID:26412349, Abstract, Results
“performed on RNA extracted from formalin-fixed paraffin-embedded tissue, performed in a central laboratory” — PMID:26412349, Methods (PMC author manuscript)
“this prospective study involving uniformly treated patients with hormone-receptor– positive, HER2-negative, axillary node–negative breast cancer supports the clinical validity of the 21-gene assay in identifying patients who may be safely spared adjuvant chemotherapy.” — PMID:26412349, Discussion (PMC author manuscript)
How these quotes were checked
Follow the passage links above to the included paper or public source record.
Full text, author manuscript. The publicly available PMC author manuscript was retrieved on 2026-09-08 and read. Abstract quotes were checked against the cached PubMed record; body-text quotes were checked by exact string match against that manuscript. An author manuscript can differ in wording from the final journal version.
Limits of this source
Only about 16% of enrolled women had a score of 0 to 10. The low-score group was not randomized, so this shows low risk without chemotherapy, not a head-to-head comparison. Full text is the author manuscript, not the journal typescript; one phrase in it runs two words together.
Review
Reviewed by Sarah Kiselycznyk · September 10, 2026. Review scope and verification method: How we researched this.