Preclinical imaging for targeting cancer immune evasion

Novel anticancer immunotherapy strategies such as immune checkpoint blockade have been successfully employed in patients with a variety of cancers and became a therapeutic option in the treatment of several malignancies. However, long-term durable responses to immune checkpoint inhibitors are currently limited to a fraction of patients raising the need of an accurate selection of potentially responding patients. Although several biomarkers have been proposed for patient selection and prediction of response to immune checkpoint blockade, none can be considered as an absolute selection criterion. Whole-body imaging with tracers recognizing targets for immunotherapy by allowing visualization of target expression in all tumor and extratumoral sites at baseline and during disease evolution may provide reliable predictive imaging biomarkers. Here we will provide an overview of preclinical imaging studies aiming at the development and validation of tracers recognizing targets for immunotherapy that can be used for selection and monitoring of patients undergoing immunotherapy and for testing novel immunotherapeutic agents or strategies. Furthermore, we will focus on the selection of animal models based on the main purpose of the study and implications for clinical transfer of the results.