Immune checkpoint regulation network in tumor-resident and healthy CD4 Tregs. (A) Network of 10 known immune checkpoint genes (orange) and 31 coexpressed candidate genes (dark green). Edge width reflects average correlation coefficient of a given gene pair across 6 FL and 2 tonsil control specimens. (B) Heat map representation of the network shown in (A). Entries represent the average correlation coefficient across the 2 tonsil specimens subtracted from the average correlation measured across the 6 FL specimens. Entries close to zero indicate that the magnitude of coexpression is similar between FL and control specimens, whereas negative and positive entries indicate overrepresentation of the corresponding coexpressed pair in tonsil and FL specimens respectively. (C-D) Two examples are shown in this context: CEBPA is coexpressed with PDCD1 in tonsils but not in FL (C), whereas CD7 is coexpressed with TNFRSF18 in both FL and tonsils (D). (Network in panel A was visualized with Cytoscape.³⁴  For panels C-D, least squares regression [line] is fitted on normalized and scaled unique molecule identifier counts for each gene pair [dots] and shown along with the standard error bounds.)