For this study we hypothesized that incorporation of PTC 209 into anti-CD49f PLGA-PEG NPs for targeted delivery will not only increase the accumulation of Bmi1 inhibitor PTC 209 into implanted breast CSC tumor and hence anti-cancer efficacy through active targeting, but will also enable improvement of its safety by using lower doses. The gene discussed is BMI1; the disease is neoplasm.