The MC09 spectral signature score (HLA‐DRB1, HLA‐DRB5, FAS, LAG3, ICOS, CXCR5, PDCD1, CTLA4) was highly enriched in DLBCL (Figure 4e), and pathway enrichment suggests a regulatory function for MC09 (Supplementary figure 6b, Supplementary table 8). Here, HLA-DRB5 is linked to diffuse large B-cell lymphoma.