These findings suggest, that PDGFR- and INSR-pathway sub-network activity in the high grade breast cancer samples of the Lu et al. (2008) data set might be relatively low compared to all other samples due to signaling modulation on the level of growth factor reception as well as on the level of the enzyme that mediates the posttranslational activation of the signaling pathway. Here, PDGFRB is linked to breast cancer.