We also examined Bregs in the tumor and found that tumor-infiltrating Bregs, like lymph node Bregs, could not be clearly divided into CD24hiIgDlo/−CD38lo and CD24hiIgDlo/−CD38hi subsets (Supplementary Fig. S9a), but also expressed a higher level of PPARδ and produced more IL-10 (though not as high as splenic and blood Bregs; Fig. 2e–g and Supplementary Fig. S5b, c) than mature (CD24loIgDhi) B cells (Supplementary Fig. S9b, c). The gene discussed is PPARD; the disease is neoplasm.