IKZF4 and neoplasm: In bulk RNA-seq data comparing Treg cells from healthy colon biopsies and tumor tissue from individuals with colorectal cancer27 (Fig. 6f and Extended Data Fig. 8d), we found elevated IL23R expression in tumor Treg cells, which coincided with increased expression of FOXP3 and its target genes IL2RA, IKZF4, ENTPD1 (encoding CD39) and TNFRSF18 (encoding GITR; Fig. 6f).