Therapeutic nanosystems for oncology nanomedicine.

Cancer is a complex disease which includes many pathologies featuring abnormal growth of healthy cells, invasion and metastization. Cellular uncontrolled growth increases the amount of abnormal cells, these cells reach the blood stream and other healthy tissues giving rise to secondary tumors. Even though great progresses have been made in understanding cancer aetiology and in the development of new anticancer drugs, cancer still remains one of the leading causes of death worldwide. Most common cancers include breast cancer, lung cancer, colorectal cancer and brain cancer. Conventional chemotherapeutics have proven to be inefficient in cancer treatment due to lack of specificity and poor drug accumulation in tumors. In addition, they cause severe side effects. Available treatments must be prolonged on time to achieve some therapeutic effect; however, this often leads to the development of multidrug resistance by tumor cells. Nanotechnology platforms are, therefore, being exploited as potential alternatives. Nanosystems have been reported to target and deliver the drug in situ to selectively kill cancer cells, decreasing toxicity on healthy organs and tissues as well as side effects. Furthermore, some nanosystems have been reported to overcome tumor resistance, at least to some extent. Over the years several nanosystems have been proposed to diagnose and treat cancers, such as dendrimers, polymeric micelles, superparamagnetic iron oxide cores, gold nanoparticles, liposomes and other lipid nanoparticles. Due to their small size and biocompatibility, they can reach the target site without being detected by the immune system and suffer cellular uptake or deliver the drug in the tumor vicinity.