Treatment of p18−/−;Brca1MGKO tumor cells with PDGFR Inh III and Ro-31-8220 significantly reduced cell number and increased cell death, particularly with high dosages (200 nM for PDGFR Inh III and 350 nM for Ro-31-8220) (Fig. 5b, c). This evidence concerns the gene PDGFRB and neoplasm.