To evaluate the impact of selective PDGFRβ inhibition of stromal cells on tumor growth we investigated four tumor cell lines with no or low PDGFRβ expression, i.e. Lewis lung carcinoma (LLC), EO771 breast carcinoma, B16 melanoma and a version of B16 that had been engineered to overexpress PDGF-BB (B16/PDGF-BB). This evidence concerns the gene PDGFRB and breast carcinoma.