PDGFRB and neoplasm: Using western blots to assess protein, we found that the expression of Pdgfrβ, p-Pkcα, and p-Fra1 was clearly increased in p18−/−;Brca1MGKO tumors relative to that of adjacent tumor-free mammary tissues in the same mice or to p18−/− tumors (Fig. 2d, Additional file 4), and in p18−/−;Brca1MGKO tumor cells relative to that in p18−/− tumor cells (Fig. 2e).