Tumor infiltrating B cells and tertiary lymphoid structures in pancreatic cancer prognosis and therapy.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, characterized by a profoundly immunosuppressive tumor microenvironment (TME) that limits response to immunotherapy. Tumor-infiltrating B cells (TIBs) constitute a key TME component, and in certain patient subsets, they collaborate with T cells, dendritic cells, and other immune cells to form tertiary lymphoid structures (TLSs). Current evidence reveals functionally distinct TIB subsets in PDAC; while some subsets promote tumor progression, others enhance anti-tumor immunity. Therefore, comprehensively elucidating these dualistic roles is imperative. Concurrently, the presence of mature TLSs within PDAC correlates with improved prognosis and therapeutic outcomes. Understanding TIB and TLS dynamics, along with their interactions with other TME components, may unveil novel strategies to overcome immune suppression in PDAC. This review synthesizes recent advances in TIB and TLS research, evaluates their prognostic significance, and explores potential clinical applications.