CXCR4 and neoplasm: In addition, the CXCL12/CXCR4/SATB-1 axis, which has been demonstrated to be upregulated by gemcitabine, mediates a reciprocal feedback loop between pancreatic cancer and CAFs to maintain their gemcitabine-resistant properties [101], and CXCL12/CXCR4 also plays roles in preventing CD8+ T cells and recruiting Tregs and macrophages’ access to tumor cells [102].