The evidence further suggests that TCR triggering of BM tumor antigen-specific Tregs, but not Tconvs, induces tumor cell egression from the BM into the peripheral blood and tumor tissue, mediated by emigration receptor S1P1 and homing receptor CCR2, providing a plausible mechanism for bone metastasis reducing systemic antitumor immunity [82]. This evidence concerns the gene S1PR1 and neoplasm.