Received: 21 February 2017 Revised: 19 June 2017 Accepted: 30 June 2017 DOI: 10.1002/med.21462 REVIEW ARTICLE Anti-MUC1 aptamer: A potential opportunity for cancer treatment Maryam Sadat Nabavinia 1 Aida Gholoobi 2 Fahimeh Charbgoo 1,3 Mahboobeh Nabavinia 4 Mohammad Ramezani 1,5 Khalil Abnous 3,6 1 Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran 2 Department of Modern Sciences and Technolo- gies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 3 Pharmaceutical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran 4 Department of Bioengineering, University of Illinois, Chicago, IL 5 Nanotechnology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran 6 Department of Medicinal Chemistry, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran Correspondence Mohammad Ramezani, Department of Medic- inal Chemistry, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran. E-mail: Ramezanim@mums.ac.ir Khalil Abnous, Pharmaceutical Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran. E-mail: Abnouskh@mums.ac.ir. Abstract Mucin 1 (MUC1) is a protein usually found on the apical surface of most normal secretory epithelial cells. However, in most adenocar- cinomas, MUC1 is overexpressed, so that it not only appears over the entire cell surface, but is also shed as MUC1 fragments into the blood stream. These phenomena pinpoint MUC1 as a potential tar- get for the diagnosis and treatment of cancer; consequently, inter- est has increased in MUC1 as a molecular target for overcoming cancer therapy challenges. MUC1 currently ranks second among 75 antigen candidates for cancer vaccines, and different antibodies or aptamers against MUC1 protein are proving useful for tracing can- cer cells in the emerging field of targeted delivery. The unique prop- erties of MUC1 aptamers as novel targeting agents, and the revolu- tionary role that MUC1 now plays in cancer therapy, are the focus of this review. Recent advancements in MUC1-targeted cancer therapy are also assessed. KEYWORDS antibody, aptamer, mucin 1 or MUC1, targeted therapy 1 INTRODUCTION The mucin family of heavily O-glycosylated proteins is classified into two subfamilies—cell surface associated and secreted (gel-forming) mucins—based on their biochemical properties and cell surface location. One member of the membrane-bound mucin subfamily is MUC1. 1 This protein exists on the apical cell surface of most normal secre- tory epithelial cells and, to a lesser degree, on hematopoietic cells. 1 However, it is abnormally overexpressed in many cancers, including 96.7% of invasive lung cancers; 2 90% of pancreatic, 3 prostate, 4 epithelial ovarian, and platinum- resistant tumors; 5 77% of primary lung cancers; 2 70% of breast cancers; 6 58% of primary lesions of prostate cancer; and 60% of captured circulating tumor cells from metastatic breast, lung, pancreatic, and colon cancers. 7 This differ- ence in the expression of normal MUC1 and tumor-associated MUC1 (TA-MUC1) makes this protein an attractive tumor-associated marker for diagnostic, drug delivery, and immunotherapy approaches for cancer treatment. 8 Med Res Rev 2017;1–22. wileyonlinelibrary.com/journal/med c  2017 Wiley Periodicals, Inc. 1