A new gene expression signature related to breast cancer Estrogen Receptor status

Abstract — The aim of this study is to identify a gene signature which is characteristic of ER status in breast cancer patients. To our knowledge, this is the first microarray study in Greece concerning breast cancer. We identified 97 genes that are characteristic for ER status and can well distinguish the ER+ from the ER- samples. We also managed to shrink our list to a 11-gene list giving the same prognostic outcome. We found a significant overlap of these genes with published prognostic signatures like the ones of West et.al. [4] and of Van’t Veer et. al. [1]. This fact is very encouraging given the minimal overlap of such genes reported by others [28]. In order to give a meaningful information to the doctors we found associations with biological pathways. Interestingly, the vast majority of these genes are highly related to breast cancer. I