The role of mast cells in cancers

Mast cells are immune cells that accumulate in the tumors and their microenvironment during disease progression. Mast cells are armed with a wide array of receptors that sense environment modifications and, upon stimulation, they are able to secrete several biologically active factors involved in the modulation of tumor growth. For example, mast cells are able to secrete pro-angiogenic and growth factors but also pro- and anti-inflammatory mediators. Recent studies have allowed substantial progress in understanding the role of mast cells in tumorigenesis/disease progression but further studies are necessary to completely elucidate their impact in the pathophysiology of cancer. Here we review observations suggesting that mast cells could modulate tumor growth in humans. We also discuss the drawbacks related to observations from mast cell-deficient mouse models, which could have consequences in the determination of a potential causative relationship between mast cells and cancer. We believe that the understanding of the precise role of mast cells in tumor development and progression will be of critical importance for the development of new targeted therapies in human cancers.