Thinking small, doing big: Current success and future trends in drug delivery systems for improving cancer therapy with special focus on liver cancer.

Nanotechnology has recently emerged as a promising tool in biomedicine research. An important branch of nanotechnology is drug delivery and drug targeting using a wide range of biomaterials with promising potential applications in cancer research. The aim of this review is to provide an overview of the evolution of nanotechnology in cancer therapy, exemplified by a myriad of applications in drug delivery, tumor targeting and reversal of ATP-binding cassette drug transporter-mediated multidrug resistance (MDR) in cancer cells by the biomaterials used in nanoformulations. Special attention will be focused on liver cancer, especially, on hepatocellular carcinoma, which is among the malignancies with the poorest prognosis due to its extremely "difficult-to-treat" nature related to its high recurrence rate and MDR phenotype.