%0 Journal Article %T Clinical Studies Applying Cytokine-Induced Killer Cells for the Treatment of Gastrointestinal Tumors %A Clara E. J£¿kel %A Annabelle Vogt %A Maria A. Gonzalez-Carmona %A Ingo G. H. Schmidt-Wolf %J Journal of Immunology Research %D 2014 %R 10.1155/2014/897214 %X Tumors of the gastrointestinal system represent a significant share of solid tumors worldwide. Despite the advances in diagnosis and treatment, the prognosis of gastrointestinal tumors is still very poor and improved therapies are indispensable. Cytokine-induced killer (CIK) cells are feasible for an immunotherapeutic approach as they are easily available and have an advantageous biologic profile; they are rapidly proliferating and their high cytotoxicity is non-MHC-restricted. We summarize and discuss twenty recent clinical studies applying CIK cells for the treatment of gastric, pancreatic, hepatocellular, and colorectal cancer. Autologous CIK cells were transfused intravenously, intraperitoneally, or via the common hepatic artery. In all studies side effects and toxicity of CIK cell therapy were mild and easily controllable. The combination of CIK cell therapy with conventional adjuvant or palliative therapies was superior to the standard therapy alone, indicating the benefit of CIK cell therapy for cancer patients. Thus, CIK cells represent a promising immunotherapy for the treatment of gastrointestinal tumors. The optimal treatment schedule and ideal combination with conventional therapies should be evaluated in further clinical studies. 1. Introduction Tumors of the gastrointestinal (GI) system constitute a major part of the cancer incidence and mortality statistics. Worldwide, colorectal cancer is the most frequent type of GI cancer: it is the third most common cancer in men and the second most common in women. Moreover, colorectal cancer accounts for the largest share of GI cancer-related deaths in women, while liver cancer is the most common cause of death among GI tumors of men [1]. Despite the recent advances in diagnosis and therapy, outcomes for patients with GI tumors remain very poor. Often, GI tumors are diagnosed only at advanced stages due to the lack of specific symptoms and screening methods. As a result, 5-year survival rates are low [2¨C5]. Adoptive cell immunotherapy might be used in combination with standard therapies¡ªas adjuvant postsurgical treatment and as palliative treatment¡ªto improve survival and quality of life of GI cancer patients. Cytokine-induced killer (CIK) cells have the best credentials to be effective in this therapeutic approach. Compared to lymphokine-activated killer (LAK) cells, CIK cells can be obtained more easily and reveal a higher tumor-specific cytotoxic activity [6¨C10]. Similarly, there are several factors hampering the adoptive cell therapy with tumor-infiltrating lymphocytes (TILs), for example, the %U http://www.hindawi.com/journals/jir/2014/897214/