The Impact of Gene Expression Patterns in Breast Cancer.

Abstract

Featured Article: Sorlie T, Perou CM, Tibshirani R, Aas T, Geisler S, Johnsen H, et al. Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications. Proc Natl Acad Sci USA 2001;98:10869–74.2 In our 2001 article highlighted here, my colleagues and I demonstrated for the first time the clinical impact of the main 5 “intrinsic” molecular subtypes of breast carcinomas. Shortly before, we had published the identification of unique “molecular portraits” of human breast tumors based solely on variation in gene expression patterns (1). The pervasive order and interpretation of these patterns indicated that the tumors could be classified into distinct biological groups based on overall molecular commonalities. The basal-like, ERBB2 (erb-b2 receptor tyrosine kinase 2)-positive,3 and normal-like subtypes all showed low or no expression of the estrogen receptor (ER) and other genes characteristic of luminal epithelial cells and had additional features specific for each of the 3 subtypes. For example, basal-like tumors showed high expression of the basal cytokeratins 5 and 17 and epidermal growth factor receptor and represented the predominant breast cancer subtype among BRCA1 (breast cancer 1) carriers (2). Luminal …