TFRC and neoplasm: The latter two markers were analyzed based on data in the literature and data from our laboratory: genes encoding for OX40 and CD71 belong to a conserved tumor-specific Treg signature that has been identified in a meta-analysis by Zheng et al. [127]; moreover, we demonstrated that OX40 expression is distinctive of a proliferating, stable and highly suppressive activated Treg subset in tumor tissue [128,129].