In vivo imaging results showed that the two drugs-loaded NPs (NP-TAX–siRNA) accumulated mainly in the tumor tissues, because of the passive targeting ability from the enhanced penetration and retention (EPR) effect of tumor vessels [37, 38], and inhibited tumor growth dramatically, further confirming that MTDH silencing effectively enhances the TAX therapeutic efficiency. The gene discussed is MTDH; the disease is neoplasm.