Potential cardiac risk of immune-checkpoint blockade as anticancer treatment: What we know, what we do not know, and what we can do to prevent adverse effects

Cancer immunotherapy has become a well-established treatment option for some cancers after the development of a family of drugs targeting the so-called immune checkpoints, such as CTLA4 and PD-1 with PD-L1. These co-receptors/ligands inhibit the activation of T-cell, thus preventing an excessive inflammatory response. Tumors exploit these pathways to induce immune tolerance to themselves. Thus, the main effect of checkpoint-blocking drugs is to awake an immune response primarily directed against cancer cells. Nonetheless, as the immune response elicited by these drugs is not completely tumor-specific, their use may actually cause several adverse effects, including adverse cardiovascular effects. In this review, we will discuss the principles and potentiality of immunotherapy for cancer treatment, the experimental and clinical data on the role of CTLA4 and PD-1 with PD-L1 as immune-checkpoints in the cancer environment and in the cardiovascular system, and strategies aimed at preventing possible cardiovascular adverse effects of immune-checkpoint blockers.