Biological Carrier Molecules rmm.mazums.ac.ir Res Mol Med, 2016; 4 (3): 3 Targeted Cancer Diagnostic and Therapeutic Agents: Delivery by Carriers or Conjugation Mohsen Mohammadgholi 1 , Farzaneh Rezazadeh 1 , Nourollah Sadeghzadeh 1 * 1 Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran. Received: 11 May 2016 Revised: 15 Jun 2016 Accepted: 28 Jun 2016 Corresponding Author: Nourollah Sadeghzadeh, Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Mazandaran, Sari, Iran. Tel: +981133543695. E-mail: nourollahsadeghzadeh@yahoo.com Abstract Receptors and proteins are overexpressed in many human cancer cell membranes rather than normal tissues and are considered as the main molecular targets. Specific tumor- targeting molecules which have high affinity for these receptors can be valuable tools as carrier molecules for targeted cancer therapy and imaging. Pharmacokinetics and bioavailability of diagnostic and therapeutic agents are very important. Poor selectivity of cancer therapeutic agents causes toxicity on normal cells that limits maximum effective dose. The Attachment of these agents to macromolecules or their installation on carriers is currently under investigation. This article presents recent developments in the field of targeting agents and introduces different carriers and their applications in the diagnosis and treatment of cancer. Keywords: Cancer diagnosis; Cancer therapy; Biological carrier molecules; Diagnostic agent; Therapeutic agents Introduction Cancer is still one of the major causes of death worldwide. Generally, surgery, chemotherapy and radiation therapy are used for treatment of cancer. There is a balance between division, senescence and differentiation in the healthy cells, but the difference in malignant cell cycle kinetics and gene expression levels make them very susceptible to bombardment with cell proliferative inhibitors or toxic agents. Similarly, normal cells that rapidly proliferate like malignant cells are highly subject to damage by cytotoxic drugs. Bone marrow, hair follicles, and intestinal epithelium have quick turnover which results in more sensitivity to chemotherapeutic agents. Tumor cells consume glucose more than normal cells but have low efficiency and are hypoxic. Hypoxic cells are resistant to radiation whether externally or internally. One of pathophysiological characteristics of tumors is rapid vascularization with poor lymphatic drainage which makes them accessible for targeting agents (1-3). Enzymes (4, 5), receptors (6, 7) and factors (8, 9) which are more expressed in cancerous cells can be restrained by various inhibitors. Oncogenes can be damaged by DNA cross linkers, resulting in DNA synthesis inhibition and malfunction. Multidrug resistance was also observed in tumor cell population that was exposed to some anticancer drugs. Targeted drug delivery (10), also named smart drug delivery is a method of delivering imaging or therapeutic agents to a patient in a manner that increases the concentration of these agents in some parts of the body compared to others. Several radionuclides can be used to label biomolecules or carrier systems for noninvasive imaging of tumors in single photon emission computed tomography (SPECT) or positron emission tomography camera (PET) (11, 12). Researchers were interested to design 99m Tc radiolabeled systems with high target to non- target biodistribution ratio, high pictorial resolution, appropriate clearance and pharmacokinetic and simple preparation in imaging centers. In this review article, we describe biological and nanocarrier agents as valuable tools for cancer diagnosis and therapy. We Research in Molecular Medicine Review Article 2016, Vol: 4, Issue: 3, Pages: 3-9 DOI: 10.18869/acadpub.rmm.4.3.3 Please cite this article as: Mohammadgholi M, Rezazadeh F, Sadeghzadeh N. Targeted Cancer Diagnostic and Therapeutic Agents: Delivery by Carriers or Conjugation. Res Mol Med. 2016; 4 (3): 3-9