IL21 and breast cancer: Infiltrating Tfh cells play a protective role in breast cancer.[16] In ovarian cancer, Tfh cells are significantly enriched among TILs and are related to IL-21 and IL-10 secretion.[17] Moreover, infiltrating Tfh cells participate in anti-tumor immunity in NSCLC patients, and are associated with favorable clinical outcomes.[18,19] Our results were consistent with previous studies which show that Tfh cells were predictive of a good prognosis.