A data mining approach was first used to examine RGS2 expression in a set of gene expression data from normal breast samples (10 pooled isolates of freshly separated normal luminal cells) and breast cancers (15 freshly isolated infiltrating ductal carcinomas of grade 2 or 3, from which cells expressing the desmosplastic fibroblast antigen F19 had been removed) analyzed by four different gene expression microarray platforms and massively parallel signature sequencing [29]. Here, RGS2 is linked to breast cancer.