CXCL12 and neoplasm: In this regard, an interesting mechanism has been described by which senescent tumor cells prevent CD8+ T lymphocytes from infiltrating the tumor: among the components of the SASP produced by senescent tumor cells of subjects with CRC, there is chemokine (C-X-C motif) ligand 12 CXCL12/colony-stimulating factor 1 (CSF1), which plays a primary role in the exclusion and activation of CD8+ T lymphocytes.