Prioritization of cancer antigens: keeping the target in sight

Amid an evolving landscape of anticancer agents, numerous approaches to elicit tumor-specific immune responses are under active investigation. In broad terms, these approaches have traditionally included passive and active immunotherapies, whereby cells, antibodies or cytokines with antitumor activity are delivered to the recipient, or are used to elicit antitumor immunity in the host. More recently, immune-modulatory approaches, including the use of T-cell checkpoint inhibitors or agents that can affect T-cell or antigen-presenting cell function, have been studied. Most clinical trials with individual immune agents, and vaccines in particular, have demonstrated limited success despite demonstrations of biological activity. it has thus become apparent that successful immunotherapy approaches to the treatment of cancer will probably require combinations of treatment modalities. This presents a challenge, however, given the multitude of vaccine approaches currently being tested and the even greater number of vaccine target antigens being evaluated. in a recent report by the National Cancer Institute Translational Research Working Group, Cheever and colleagues attempt to tackle this problem by developing weighted criteria by which to both rank and prioritize tumor vaccine antigens. This article attempts to provide some background for the importance of this effort, discusses the methods used and potential biases introduced, and attempts to put this in context with other investigations in the tumor immunology field.