IL17A and neoplasm: Effector Th17 cell responses and IL‐17 have emerged as mediators of lymphoid neogenesis in various chronic inflammatory or autoimmune models.35, 40, 41 Interestingly, analysis of non‐tumour tissue from GC patients in TCGA data sets revealed that IL17A expression correlated significantly with that of CXCL13 and CCL19 (Supporting Information Fig. S2).