Cancer and Immune Response: Old and New Evidence for Future Challenges

Abstract

Learning Objectives: After completing this course, the reader should be able to: Discuss the current scientific background of immunotherapy applied to cancer treatment.Suggest lines of future investigation in the immunotherapy field.Explain the rationale for developing and discuss the current status of new immunotherapeutic approaches in solid tumors. CME This article is available for continuing medical education credit at http://CME.TheOncologist.com Cancer may occur as a result of abnormal host immune system tolerance. Recent studies have confirmed the occurrence of spontaneous and induced antitumor immune responses expressed as the presence of tumor-infiltrating T cells in the tumor microenvironment in some cancer models. This finding has been recognized as a good prognostic factor in several types of tumors. Some chemotherapy agents, such as anthracyclines and gemcitabine, are effective boosters of the immune response through tumor-specific antigen overexpression after apoptotic tumor cell destruction. Other strategies, such as GM-CSF or interleukin-2, are pursued to increase immune cell availability in the tumor vicinity, and thus improve both antigen presentation and T-cell activation and proliferation. In addition, cytotoxic T lymphocyte antigen 4–blocking monoclonal antibodies enhance immune activity by prolonging T-cell activation. Strategies to stimulate the dormant immune system against tumors are varied and warrant further investigation of their applications to cancer therapy in the future.