Landscape of B lymphocytes and plasma cells in digestive tract carcinomas

Digestive tract carcinomas are the most commonly occurring cancers worldwide, but their prognosis with traditional treatments remains poor. T lymphocytes are well-recognized as crucial components of effective anti-tumor immunity, and current immunotherapeutic strategies concentrate mainly on T-cell-mediated immunity reinforcement, whereas the role of B lymphocytes and plasma cells (PCs) has been neglected in the past, and it is only recently that these cells have been considered as key players in the tumor microenvironment (TME). In this review, we describe the complex dual role of B lymphocytes and PCs in promoting and inhibiting tumor progression in the TME of digestive tract carcinomas, and we demonstrate their prognostic value. Furthermore, we highlight their controversial function in cancer and nominate them as additional therapeutic targets for the development of new treatment interventions that might alter the dismal prognosis of digestive tract tumors.