Immunotherapy for lung cancer: advances and prospects

Abstract

Lung cancer is the most commonly diagnosed cancer as well as the leading cause of cancer-related deaths worldwide. To date, surgery is the first choice treatment, but most clinically diagnosed cases are inoperable. While chemotherapy and/or radiotherapy are the next considered options for such cases, these treatment modalities have adverse effects and are sometimes lethal to patients. Thus, new effective strategies with minimal side effects are urgently needed. Cancer immunotherapy provides either active or passive immunity to target tumors. Multiple immunotherapy agents have been proposed and tested for potential therapeutic benefit against lung cancer, and some pose fewer side effects as compared to conventional chemotherapy and radiotherapy. In this article, we discuss studies focusing on interactions between lung cancer and the immune system, and we place an emphasis on outcome evidence in order to create a knowledge base well-grounded in clinical reality. Overall, this review highlights the need for new lung cancer treatment options, with much ground to be paved for future advances in the field. We believe that immunotherapy agents alone or with other forms of treatment can be recognized as next modality of lung cancer treatment.

Keywords: Lung cancer; checkpoint inhibitor; immunology; immunotherapy; vaccines.

Figure 1

The tumor microenvironment (TME) is facilitated by many distinct cell types, including endothelial cells and their precursors, pericytes, myeloid-derived suppressor cells (MDSCs), cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), T and B lymphocytes, natural killer (NK) cells, dendritic cells (DCs), neutrophils, eosinophils, basophils, and mast cells.

Figure 2

Improved therapeutic efficacy can be achieved by modulating immune checkpoints, including activation of effector cells by blocking CTLA4 or PD-1.

Figure 3

Immunotherapeutic strategies for lung cancers: administration of immune checkpoint inhibitors, cancer vaccine therapy, adoptive transfer of immune cells generated in vitro, immunotherapy with dendritic cells (DCs), and recombinant cytokines.