The classic view that the role of immune cells in cancer is primarily one of tumor rejection
has been supplanted by a more complex view of leukocytes having both pro-and anti-tumor
properties. This shift is due to the now well recognized capabilities of several myeloid cell
types that foster pro-tumor programming of premalignant tissue, as well as the discovery that
subsets of leukocytes also suppress development and effector functions of lymphocytes
important for mediating anti-tumor immunity. In this review, we focus on the …