CXCL13 and lung cancer: CXCL13 and Lymphotoxin have been identified as two factors critical to the formation and development of lymphoid follicles in the gut [84], and in lung cancer, B cells produce CXCL13 and Lymphotoxin via TLR4 signalling which acts as a positive feedback loop to support the formation and high density of TLS [85, 86].