Analysis of mRNA gene expression in breast cell lines and normal tissue. (a) Analysis of differentially expressed mRNAs. Clustering heatmap for genes with analysis of variance B values of greater than 10 after either a median or a quantile normalisation. Cell type origin (B, basal; L, luminal; N, normal; S?, possible stem cell) and status of oestrogen receptor/progesterone receptor (ER/PR) are indicated on the left. mRNA clusters are indicated by purple letters (below, with their key enriched process) and purple arrows (above and below). ECM, extracellular matrix; VR, viral response. (b) Analysis of luminal/basal mRNA markers. The average log2 intensity of expression of 252 luminal and 360 basal annotated non-redundant markers is shown.