Leveraging T cells for cancer immunotherapy.

T cells play an essential role in tumour prevention and control, however, avoidance or disruption of anti-tumour T cell responses frequently leads to tumour progression and malignant disease. Immunotherapy aims to address this breakdown in T cell-mediated anti-tumour immunity and restore T cell function to promote the elimination of cancerous cells. Although immunotherapy has led to drastic improvements in patient prognoses across a range of clinical setting, most patients still fail to exhibit a durable therapeutic response. In this review we discuss the role of T cells in controlling tumour progression, how T cell immunity is avoided or disrupted in the context of malignant disease, and the mechanisms by which soluble, cellular, or vaccine-based immunotherapies aim to restore anti-tumour T cell responses. This review does not aim to provide a comprehensive summary of approved immunotherapies, nor does it focus on the logistical challenges faced during the development or clinical application of immunotherapy. Instead, this review aims to highlight the mechanisms by which different therapeutic approaches address, or fail to address, specific aspects of the breakdown in T cell-mediated anti-tumour immunity. This review will also discuss exciting pre- and early-stage clinical developments that may improve the therapeutic efficacy and applicability of these treatments by more comprehensively addressing the challenges faced by T cells to improve patient prognoses.