(101) found that another immunoregulatory cytokine, IL-27, was able to drive the expression of a module of co-inhibitory immune-checkpoint proteins, including the combination of PD-1, TIM-3, LAG-3, TIGIT, and a range of atypical immune-checkpoint proteins, which is mediated by the downstream co-regulation of PR domain zinc finger protein 1 (PRDM1) and c-musculoaponeurotic fibrosarcoma (c-MAF) transcription factors. Here, PRDM1 is linked to fibrosarcoma.