title: Breast carcinomas expressing basal markers have poor clinical outcome regardless of estrogen receptor status.
abstract: To evaluate the clinical significance of gene expression-based classification and define the characteristic features of the new basal-like subtype, invasive breast carcinomas were divided into ER, HER2, basal-like and null subtypes by immunohistochemical analysis. A total of 401 invasive breast carcinomas were submitted to tissue microarray and stained with ER, HER2, EGFR, c-KIT and cytokeratin (CK) 5/6. The basal-like tumors, defined as positive for one or more basal markers but negative for both ER and HER2, comprised 18.5%. They were larger (p=0.041), showed higher grade (p<0.001), and more frequently expressed p53 (p=0.003). Expression of the basal marker itself showed negative prognostic effect, particularly in node-positive group. Even ER-positive patients had far shorter disease-free survival (DFS) when the tumor coexpressed one or more basal marker (p<0.001). Discrimination of basal-like subtype or tumors positive for basal markers may be clinically significant also in the treatment and prognosis of breast carcinomas.
authors.affiliation: Department of Pathology, Korea University Guro Hospital, Seoul 152-703, Korea.
authors.forename: Bong Kyung
authors.initials: BK
authors.lastname: Shin
authors.forename: Youngseok
authors.initials: Y
authors.lastname: Lee
authors.forename: Jung Bok
authors.initials: JB
authors.lastname: Lee
authors.forename: Han Kyeom
authors.initials: HK
authors.lastname: Kim
authors.forename: Jae Bok
authors.initials: JB
authors.lastname: Lee
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Cho
authors.forename: Aeree
authors.initials: A
authors.lastname: Kim
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis* / Q000378:metabolism; D001943:Breast Neoplasms / Q000145:classification* / Q000175:diagnosis* / Q000473:pathology; D002277:Carcinoma / Q000145:classification* / Q000175:diagnosis* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000145:classification / Q000473:pathology; D018276:Carcinoma, Medullary / Q000145:classification; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D011379:Prognosis; D011960:Receptors, Estrogen / Q000032:analysis*
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen