Li et al. developed hyaluronic acid/poly(lactic-co-glycolic acid)-poly(ethyleneimine) nanoparticles (PP-HA/NPs) co-delivering doxorubicin/quercetin, which downregulated Akt phosphorylation and MMP-9 expression, significantly inhibiting breast cancer cell invasion [153]. The gene discussed is MMP9; the disease is breast carcinoma.