Identification of novel kinase targets for the treatment of estrogen receptor-negative breast cancer.

Purpose: Previous gene expression profiling studies of breast cancer have focused on the entire genome to identify genes differentially expressed between estrogen receptor (ER) alpha-positive and ER-alpha-negative cancers.

Experimental Design: Here, we used gene expression microarray profiling to identify a distinct kinase gene expression profile that identifies ER-negative breast tumors and subsets ER-negative breast tumors into four distinct subtypes.

Results: Based on the types of kinases expressed in these clusters, we identify a cell cycle regulatory subset, a S6 kinase pathway cluster, an immunomodulatory kinase-expressing cluster, and a mitogen-activated protein kinase pathway cluster.