Interestingly, we observed a high expression of S1P1 only on tumor antigen-specific Treg in the BM, while S1P1 expression was low on CD25+ FoxP3+ Treg, CD25-FoxP3-Tcon, tumor specific Tcon in PB and BM, and tumor specific Treg in PB (Fig. 2c, d). Here, S1PR1 is linked to neoplasm.