Nanomaterials for reversion of multidrug resistance in cancer: a new hope for an old idea?

Cancer is a major cause of mortality in the modern world, with more than 10 million new cases every year. This out-line is expected to rise in the next few decades since the majority (59%) of peo-ple diagnosed with cancer is aged over 65. In fact, around one in three people will be diagnosed with cancer throughout their lifetime (Siegel et al., 2012; Bosetti et al., 2013). The foundation of cancer treatment is surgery, chemotherapy, radiation, antibody-blocking therapy, or a com-bination of these therapies (Hanahan and Weinberg, 2000). Still, many clinical chemotherapeutic and radiotherapeutic regimes are not exceptionally effective, due to multidrug resistance mechanisms, depending on the patient and the type of tumor. Therefore, there is an urgent need for more effective and valuable cancer therapeutics, in order to reduce the impact of the chemotherapeutic agents on the healthy tissues by creating more selective systems toward the cancerous cells (Alison, 2001; Perez-Tomas, 2006). Multi-drug resistance (MDR) in can-cer refers to the capacity of cancer cells to survive or become resistant from treat-ment of a wide variety of drugs. Cancer chemotherapy has become progressively sophisticated within the last years; how-ever there are not any cancer therapies 100 % effective against disseminated can-cer. This is in fact a major problem once approximately 70 % of patients do not respond to initial chemotherapy and the five-year survival rate for these patients is a low 10–30%. Relapse is also frequen