CXCL12 and neoplasm: Further, it has been shown in vitro, in a fibroblast specific protein (FSP) driven Tgfbr2 KO (Tgfbr2FSPKO) model, the fibroblasts upregulate SDF1 [112], which is a molecule that promotes tumor progression directly by inducing tumor cell proliferation and migration, and indirectly via induction of immunosuppressive myeloid-derived suppressor cells [113,114,115,116].