Targeted cancer therapy: review article

Cancer is one of the most dangerous health problems of today modern societies which has an increasing rate especially in developing countries. There are many diverse ongoing treatment attempts trying to defeat cancer. Despite that, scientists have been unable to find a permanent cure for this disease. In many cases although there is a successful first response in patients, cancer cells are finally able to withstand therapeutic procedures and even use chemo-resistance to take advantage of treatments to facilitate tumor growth, resulting in cancer remission. Therefore, and mostly in recent two decades, scientists have been trying to choose their treatments just as smart to be able to conquer cancer. One of the best methods of this smart defense is to target weak points of neoplastic cells and use them for designing drugs. In this case it would be most probable for cancer cells not to have a chance to confront and cause chemo-resistance. Total endeavors to fulfill this goal are named “targeted cancer therapy”. This therapeutic approach is mostly consisted of two different procedures: 1- designing and using specific drugs to target cancer cells’ mutated genes; which will be defined by checking the genetic background of tumor cells for each specific cancer type. EGFR, RAS, VEGF and HIF-1α are among the pathways that have already been used as targets. 2- The other procedure could be methods that would carry drugs directly to unhealthy cells to prevent further side effects for normal cells of patients. It would be possible by designing specific antibodies to target antigens of neoplastic cells. Ribonucleic sequences (miRNAs and siRNAs) are also very promising as new drugs and nanoparticles have enabled us to increase drug concentration in tumors. The ultimate goal of these new experiments is to suggest specific drugs for each patient based on the nature of one's disease and genetic background, which will bring about "personalized medicine" era. Using valid new references, this review article first presents targets that are currently being used for this targeted therapy, their logic of choice and the drugs that have already been produced for clinical trials. Smart methods of drug delivery are also presented and discussed afterwards.