en Cancer Biology Cancer Biology مقاله مروری Review Article <div style="text-align: justify;"><span style="font-family:Times New Roman;"><span style="font-size:10.5pt"><span style="line-height:115%">Nanocarriers as powerful tools for delivering drugs to tumors provide new strategies for cancer treatment. These delivery systems encompass a diverse variety of structures, including polymeric nanoparticles (NPs), liposomes, dendrimers, micelles, and inorganic NPs such as gold and silica. Each type exhibits distinct physicochemical advantages that contribute to stability, drug-loading capacity, and targeting efficacy. Engineered nanocarriers can be utilized for the active targeting of tumor-specific receptors or for passive targeting of tumors via the </span></span><span style="font-size:9.0pt"><span style="line-height:115%">enhanced permeability (EPR) and retention</span></span><span style="font-size:10.5pt"><span style="line-height:115%"> effect, a characteristic of abnormal tumor vasculature. This targeting approach enables the precise delivery of the therapeutic agents at tumor sites, increasing drug efficacy while minimizing exposure to healthy tissues. The benefits of these strategies include reduced systemic adverse effects, improved bioavailability, and an optimized therapeutic index. This review examines both active and passive drug delivery systems, with a special focus on the characteristics of the EPR effect.</span></span></span></div> Nanocarriers, Drug delivery, Active targeting, Passive targeting 173 188 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-6098-1&slc_lang=en&sid=1 Parastoo Tarighi tarighi.p@iums.ac.ir 0000-0002-8038-036X No Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran. Mona Mousavi Esfahani monamousavi28@yahoo.com 0000-0002-3888-5671 No Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran. Ali Emamjomeh aliej1377@gmail.com 0009-0002-7607-4041 No Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran. Zohreh Mirjalili s.zohrehmirjalili71@gmail.com 0000-0002-7599-018X No Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. Parastoo Mirzabeygi pmirzabeygi@gmail.com 0000-0002-0075-8810 Yes Department of Clinical Pharmacy and Pharmacoeconomics, School of Pharmacy, Iran University of Medical Sciences, Tehran, Iran.