In addition, Son et al. revealed upregulation of the genes for proliferation, immune suppression, and cytokine/chemokine receptor in tumor-infiltrating Tregs in comparison to tumor-infiltrating CD4+Foxp3− conventional T cells or splenic Tregs from the same tumor-bearing mouse, confirming IL-33/ST2 axis as a critical pathway for the preferential accumulation of Tregs in the TME [116]. Here, CD4 is linked to neoplasm.