Interestingly in immune-competent mouse models of breast cancer, regulatory T cells enhance SOX2 expression by mammary cancer cells in a paracrine manner, while Sox2-expressing tumor cells recruit Tregs through NF- κB/CCL1 [Nuclear Factor kappa B/Chemokine (C-C motif) ligand 1] signaling (44). Here, CCL1 is linked to neoplasm.