Purpose of review: Cancer treatment is entering an era of targeted approaches. One such approach is use of the immune system to recognize and eliminate malignant cells. Synthetic CpG oligonucleotides (CpG DNA) are a relatively new class of agents that have the ability to stimulate a potent, orchestrated tumor-specific immune response. This review provides an overview of the immunologic effects of CpG DNA and summarizes the results of preclinical investigations that have led to ongoing development of CpG DNA as a component of clinical cancer immunotherapy.
Recent findings: New studies demonstrate that at least three classes of CpG DNA sequences exist, each with different physical characteristics and biologic effects. Preliminary studies in several animal models of cancer suggest that CpG DNA have the ability to induce tumor regression by activating innate immunity, enhancing antibody dependent cellular cytotoxicity, and serving as potent vaccine adjuvants that elicit a specific, protective immune response.
Summary: Animal models suggest that CpG DNA may have many uses in cancer immunotherapy. Early clinical trials suggest that CpG DNA can be administered safely to humans, and studies are ongoing to understand how these agents may play a role in cancer immunotherapy.