Not only do CAF-S1 secrete high levels of CXCL12, which attracted CD4+CD25+ T cells to the tumour site, but they also induced the differentiation of these cells into CD25highFOXP3high Tregs via high expression of B7-H3, CD73, and dipeptidyl peptidase-4 (DPP4, also known as CD26) in this CAF subpopulation [42]. The gene discussed is DPP4; the disease is neoplasm.