Fig. 1

Data mining of Gene expression profiles. a Significance analysis of microarray (SAM) was performed to identify differentially expressed genes between young and older breast cancer tissues. Delta was set to 0.6, and the threshold of FDR was set to 0.182. b Supervised hierarchical clustering of 553 differentially expressed genes. The heat map revealed the gene expression patterns between young patients and older patients. All samples were denoted in columns and genes were denoted in rows (gene symbols for a cluster of genes were listed on the right and the details of all differentially expressed genes could be found in Additional file 2: Table S2). The mapped expression levels for all genes were depicted using a color scale; highly expressed genes were indicated in red and lowly expressed in blue. c GO analysis of a cluster of differentially expressed genes was performed with GenCLiP software (http://ci.smu.edu.cn)