CD146 mRNA expression in human primary breast tumors. (a) Hierarchical clustering of 227 breast cancer tissue samples and 14,486 genes/Expressed Sequence Tags based on mRNA expression levels. Each row represents a gene, and each column represents a tumor. The expression level of each gene in a single tumor is relative to its median abundance across all tumors and is depicted according to a color scale shown at the bottom. Red and green, expression levels respectively above and below the median. The magnitude of deviation from the median is represented by the color saturation. The dendrogram of samples (above matrix) represents overall similarities in gene expression profiles and is magnified in (b), colored bars to the left, locations of seven gene clusters of interest. The stromal/vascular gene cluster (orange bar) includes MCAM. ER, estrogen receptor. (b) Dendrogram of breast cancer samples. (c) Expanded view of CD146/MCAM expression. Also see Additional data file 4.