PDGFRB and neoplasm: After a 9-day treatment, tumors from DMSO-treated mice reached 578 ± 265 mm3 in size, whereas those from PDGFR Inh III-treated mice only reached 131 ± 22 mm3, which was even smaller than that of the tumor size at the start of treatment (194 ± 48 mm3) (Fig. 6a), indicating that treatment with PDGFR Inh III induced regression of Brca1-deficient tumors.