CXCL13 and breast neoplasm: In this study, an increase in the CXCL13‐positive ICs in the high HER2‐AAb group indicates that the CXCL13‐positive ICs in the tumor stroma and the follicular CD4‐positive ICs found in the SLOs both stimulated the maturation of B cells and helped them to migrate to the breast tumor stroma.