Anti-tumorigenic activities of eosinophils in mucosal tumors

Eosinophils are evolutionarily conserved, pleotropic cells that display key effector functions in allergic diseases, such as asthma. Nonetheless, eosinophils infiltrate multiple tumors and are equipped to regulate tumor progression by at least two non-mutually exclusive mechanisms, namely direct interactions with tumor cells and shaping the tumor microenvironment (TME).
We will discuss the mechanisms of eosinophil homing to the TME and examine their diverse anti-tumorigenic functions. We will discuss the interactions of eosinophils with lymphocyte subsets and will present emerging data regarding eosinophils as predictive biomarkers and effector cells in immunotherapy, especially in response to immune checkpoint blockade therapy.