{"entity":{"id":"paper-sorlie-breast-carcinoma-subclasses-pnas-2001","kind":"paper","name":"Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications","aka":[],"tldr":"The 2001 follow-up showing that the gene-expression groups of breast cancer predict how patients fare, with the basal-like group doing worst; it made the subtypes clinical rather than descriptive.","summary":"Sørlie, Perou, Tibshirani, Aas and colleagues analysed 85 cDNA microarray experiments representing 78 cancers, three fibroadenomas and four normal breast tissues by hierarchical clustering. As reported earlier, the cancers separated into a basal epithelial-like group, an ERBB2-overexpressing group and a normal breast-like group; the luminal, oestrogen receptor-positive group divided into at least two subgroups with distinct profiles. The subtypes were robust to two gene sets (456 intrinsic clones and an outcome-correlated set). In a subcohort of locally advanced cancers treated uniformly in a prospective study, outcomes differed significantly by group, with a poor prognosis for the basal-like subtype and a difference between the two oestrogen receptor-positive groups.","asOf":"2026-09-24","links":[{"label":"Proc Natl Acad Sci 2001","url":"https://doi.org/10.1073/pnas.191367098"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/11553815/"}],"tags":["tnbc-evidence"],"related":["paper-perou-molecular-portraits-breast-tumours-nature-2000"],"cancers":["tnbc","breast-hr-positive","breast-her2-positive"],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["pam50"],"trials":[],"people":["charles-perou"],"bottlenecks":[],"keyPapers":[],"journals":["pnas"],"dependsOn":[],"notes":[],"journal":"Proceedings of the National Academy of Sciences","year":2001,"doi":"10.1073/pnas.191367098","pmid":"11553815","authors":"Sørlie T, Perou CM, Tibshirani R, et al.","paperType":"translational","findings":["78 cancers clustered into basal-like, ERBB2-overexpressing, normal-like and at least two luminal subgroups.","Significantly different outcomes by subtype in uniformly treated locally advanced disease; basal-like had a poor prognosis."],"whatItMeans":"The first evidence that the basal-like group is not just biologically distinct but clinically dangerous, the observation that triple-negative outcome studies of 2007 confirmed in the clinic.","caveats":["Survival analysis on a subcohort of locally advanced disease.","Microarray platforms of the period; subtype calls were later standardised as PAM50."],"changedPractice":true,"participants":78},"route":"/key-papers/paper-sorlie-breast-carcinoma-subclasses-pnas-2001/","neighbours":{"paper":[{"id":"paper-perou-molecular-portraits-breast-tumours-nature-2000","kind":"paper","name":"Molecular portraits of human breast tumours","route":"/key-papers/paper-perou-molecular-portraits-breast-tumours-nature-2000/"}],"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":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"term":[{"id":"pam50","kind":"term","name":"PAM50 / intrinsic subtypes","route":"/terms/pam50/"}],"person":[{"id":"charles-perou","kind":"person","name":"Charles M. Perou","route":"/people/charles-perou/"}],"journal":[{"id":"pnas","kind":"journal","name":"Proceedings of the National Academy of Sciences","route":"/journals/pnas/"}],"roadmap":[{"id":"tnbc-roadmap","kind":"roadmap","name":"Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem","route":"/roadmaps/tnbc-roadmap/"}]}}