Tumor-evoked regulatory B cells as important mediators of cancer escape

Our understanding of immune regulation was drastically changed by Sakaguchi's seminal discovery of regulatory T cells (Tregs). To date, the cells that exert regulatory activity are found among almost every type of immune cells. Their primary function is to control immune homeostasis and prevent aberrant autoimmune responses, making them an attractive target of cancer. In fact, cancer actively hijacks Tregs and myeloid-derived suppressive cells (MDSCs) by corrupting them in order to abrogate antitumor effector responses and to promote a cancer-benefiting milieu. However, the role of regulatory B cells (Bregs) in this process is poorly understood, despite the existence of protective IL-10-producing B cells and Bregs in autoimmune diseases. Here in this review, we discuss the pros and cons and the latest evidence of the importance of Bregs in mediation of immunosuppression required in cancer escape and metastasis.