The Role of B Cells in Solid Tumors

A surge of recent studies have identified B cells as pivotal contributors to shaping the tumor microenvironment (TME) within solid tumors. B cells can both directly and indirectly antagonize tumor growth via antibody production, antigen presentation, and cytokine secretion, potentially through the formation of tertiary lymphoid structures. However, certain B cell states have demonstrated the ability to promote tumor growth via immunoregulatory mechanisms such as the production of immunosuppressive cytokines and the expression of immune checkpoints, both of which dampen T cell–dependent antitumor responses. Here, we discuss the dichotomy of B cell function in solid tumors, underscoring both the pro- and antitumor roles that B cells play in the TME. Furthermore, we summarize ongoing efforts to reprogram protumorigenic B cells and/or to promote the activity and abundance of effector B cells as potential immunotherapy approaches in solid tumors.