The role and therapeutic implications of T cells in cancer of the lung

Lung cancer remains the leading cause of cancer‐related death worldwide. The disease is classified into two major subtypes, small‐cell lung cancer (SCLC) and the more prevalent non‐small‐cell lung cancer (NSCLC). First‐line conventional therapies, such as chemotherapy, radiotherapy and surgery, have offered limited benefit, and patient prognosis remains poor with post‐treatment recurrences representing a major cause of morbidity. Consequently, there is an urgent need for improved therapeutic options. Historically, NSCLC has been considered a non‐immunogenic disease. However, increased understanding of tumor‐immune interactions has challenged this paradigm in both lung and other malignancies, with cancer elimination by tumor‐specific T cells increasingly well described in a myriad of solid tumors. Recent evidence has demonstrated that absent or weak anticancer responses are likely a product of tumor‐derived immunosuppression. This knowledge, along with a greater appreciation for the role of T cells in lung cancer elimination, has driven development of novel immunotherapeutic approaches which are demonstrating remarkable clinical efficacy. This review examines the role of T cells in lung cancer, discussing the direction and clinical significance of current and future immunotherapeutic strategies. The tumor microenvironment plays a major role in disease progression. This review highlights relevant features of tumor immunology in the lung, with reference to current immunotherapy in the clinic and in development.