title: Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications.
abstract: The purpose of this study was to classify breast carcinomas based on variations in gene expression patterns derived from cDNA microarrays and to correlate tumor characteristics to clinical outcome. A total of 85 cDNA microarray experiments representing 78 cancers, three fibroadenomas, and four normal breast tissues were analyzed by hierarchical clustering. As reported previously, the cancers could be classified into a basal epithelial-like group, an ERBB2-overexpressing group and a normal breast-like group based on variations in gene expression. A novel finding was that the previously characterized luminal epithelial/estrogen receptor-positive group could be divided into at least two subgroups, each with a distinctive expression profile. These subtypes proved to be reasonably robust by clustering using two different gene sets: first, a set of 456 cDNA clones previously selected to reflect intrinsic properties of the tumors and, second, a gene set that highly correlated with patient outcome. Survival analyses on a subcohort of patients with locally advanced breast cancer uniformly treated in a prospective study showed significantly different outcomes for the patients belonging to the various groups, including a poor prognosis for the basal-like subtype and a significant difference in outcome for the two estrogen receptor-positive groups.
authors.affiliation: Department of Genetics, The Norwegian Radium Hospital, Montebello, N-0310 Oslo, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Sørlie
authors.forename: C M
authors.initials: CM
authors.lastname: Perou
authors.forename: R
authors.initials: R
authors.lastname: Tibshirani
authors.forename: T
authors.initials: T
authors.lastname: Aas
authors.forename: S
authors.initials: S
authors.lastname: Geisler
authors.forename: H
authors.initials: H
authors.lastname: Johnsen
authors.forename: T
authors.initials: T
authors.lastname: Hastie
authors.forename: M B
authors.initials: MB
authors.lastname: Eisen
authors.forename: M
authors.initials: M
authors.lastname: van de Rijn
authors.forename: S S
authors.initials: SS
authors.lastname: Jeffrey
authors.forename: T
authors.initials: T
authors.lastname: Thorsen
authors.forename: H
authors.initials: H
authors.lastname: Quist
authors.forename: J C
authors.initials: JC
authors.lastname: Matese
authors.forename: P O
authors.initials: PO
authors.lastname: Brown
authors.forename: D
authors.initials: D
authors.lastname: Botstein
authors.forename: P E
authors.initials: PE
authors.lastname: Lønning
authors.forename: A L
authors.initials: AL
authors.lastname: Børresen-Dale
mesh_terms: D000465:Algorithms; D001943:Breast Neoplasms / Q000145:classification / Q000235:genetics*; D002278:Carcinoma in Situ / Q000145:classification / Q000235:genetics*; D018270:Carcinoma, Ductal, Breast / Q000145:classification / Q000235:genetics*; D018275:Carcinoma, Lobular / Q000145:classification / Q000235:genetics*; D004273:DNA, Neoplasm; D005260:Female; D018226:Fibroadenoma / Q000145:classification / Q000235:genetics*; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D004273:DNA, Neoplasm; D016159:Tumor Suppressor Protein p53