CCL21 and gastric neoplasm: Homeostatic chemokines play a central role in the development of secondary lymphoid organs and TLSs,4, 12 and our earlier data revealed transcripts for Cxcl13, Ccl19, Ccl21 and Cxcl12 in laser microdissected TLSs from 6‐month‐old gp130F/F mice with well‐established gastric tumours (see Fig. 1h).