This study investigates the role of CD4+ T cells in breast cancer and their impact on patient prognosis. The researchers found that CD4+ Tfh cells, a type of follicular helper T cell, are present in breast tumors and are associated with more extensive immune infiltration. These Tfh cells produce CXCL13, a chemokine that attracts other immune cells to the tumor, leading to the formation of tertiary lymphoid structures (TLS) and germinal centers (GCs). The presence of CXCL13-producing Tfh cells was strongly correlated with improved survival and response to preoperative chemotherapy, particularly in HER2-negative subtypes. The study also identified an 8-gene signature that includes CXCL13, which predicted better clinical outcomes in patients with breast cancer. These findings suggest that CD4+ Tfh cells play a crucial role in the immune response to breast cancer and may be a valuable prognostic marker.This study investigates the role of CD4+ T cells in breast cancer and their impact on patient prognosis. The researchers found that CD4+ Tfh cells, a type of follicular helper T cell, are present in breast tumors and are associated with more extensive immune infiltration. These Tfh cells produce CXCL13, a chemokine that attracts other immune cells to the tumor, leading to the formation of tertiary lymphoid structures (TLS) and germinal centers (GCs). The presence of CXCL13-producing Tfh cells was strongly correlated with improved survival and response to preoperative chemotherapy, particularly in HER2-negative subtypes. The study also identified an 8-gene signature that includes CXCL13, which predicted better clinical outcomes in patients with breast cancer. These findings suggest that CD4+ Tfh cells play a crucial role in the immune response to breast cancer and may be a valuable prognostic marker.