Summary: Three recent studies, approaching the question from different angles and using different and/or overlapping models, provide compelling evidence for the involvement of tumor-infiltrating B cells in the initiation and progression of pancreatic ductal adenocarcinoma. These studies highlight the need for a better understanding of pancreatic tumor–immune system interactions and the immunologic mechanisms that promote or inhibit tumorigenesis, paving the way for better treatment strategies.Bloodwise (UK) (Visiting Fellowship Grant (14043))