A recent study on pancreatic ductal adenocarcinoma identified a B-cell subpopulation that supported early tumour growth by secretion of IL-35.11 Additional tumour stimulatory subsets of B-lymphocytes characterised by PD1 expression or CXCL13 secretion have also been identified in mice.29,30. The gene discussed is CXCL13; the disease is neoplasm.