Systemic chemotherapy is the main anticancer treatment for most kinds of clinically diagnosed solid tumors. However, the efficacy of anticancer drugs is often lower than expected or desired. Moreover, after a good initial reaction, the tumors often become non-responsive and resistant to the drugs. These impediments in anticancer therapy can be attributed to insufficient drug delivery to all tumor cells. If drug molecules are not able to reach all tumor cells in adequate quantities, they cannot evoke the desired effects.