TREM1 and neoplasm: Taken together, these results have demonstrated that 1) four Treg pathways including p38 MAPK signaling, IL-6 signaling, TREM1 signaling and Toll-like receptor signaling often found in non-malignant Treg are only shared in some tumor Treg but not all the tumor Treg groups (Table 2B); 2) splenic Treg from mouse bearing different tumors upregulated different pathways; and 3) tumor Treg upregulated specific pathways.