Pascual, TomásMartin, MiguelFernández-Martínez, AranzazuParé, LaiaAlba, EmilioRodríguez-Lescure, ÁlvaroPerrone, GiuseppeCortés, JavierMorales, SerafínLluch, AnaUrruticoechea, AnderGonzález-Farré, BlancaGalván, PatriciaJares, PedroRodriguez, AdelaChic, NuriaRighi, DanielaCejalvo, Juan MiguelTonini, GiuseppeAdamo, BarbaraVidal, MariaVillagrasa, PatriciaMuñoz, MontserratPrat, Aleix2025-01-072025-01-072019-04-262234-943Xhttps://hdl.handle.net/10668/26929Background: In hormone receptor-positive (HR+)/HER2-negative breast cancer, the HER2-enriched and Basal-like intrinsic subtypes are associated with poor outcome, low response to anti-estrogen therapy and high response to chemotherapy. To date, no validated biomarker exists to identify both molecular entities other than gene expression. Methods: PAM50 subtyping and immunohistochemical data were obtained from 8 independent studies of 1,416 HR+/HER2-negative early breast tumors. A non-luminal disease score (NOLUS) from 0 to 100, based on percentage of estrogen receptor (ER), progesterone receptor (PR) and Ki67 tumor cells, was derived in a combined cohort of 5 studies (training dataset) and tested in a combined cohort of 3 studies. The performance of NOLUS was estimated using Area Under the ROC Curve (AUC). Results: In the training dataset (n = 903) and compared to luminal disease, non-luminal disease had lower percentage of ER-positive cells (median 65.2 vs. 86.2%, penAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/PAM50breast cancergene expressionintrinsic subtypenon-luminalresearch article31106144open access10.3389/fonc.2019.00303PMC6498671https://www.frontiersin.org/articles/10.3389/fonc.2019.00303/pdfhttps://pmc.ncbi.nlm.nih.gov/articles/PMC6498671/pdf