CXCL13 and neoplasm: As in the case of CXCL9, IRF5 (interferon regulatory factor 5) can bind to the promoter of CXCL13 and directly regulate its expression in mammary epithelial tumor cells leading to the infiltration of CD19+CXCR5+ B-cell and CD4+CXCR5+ T-cell to the tumor (41).