CCL21 and cancer: It represents the catalytic subunit of TORC1 and TORC2, two distinct complexes linked by a negative feedback loop, able to regulate different functions and downstream targets [27].The above described results indicated that both complexes are activated in skin-derived SS cells; however, the finding that TORC1 pathway is triggered in cancer cells by SDF-1 and CCL21 [28–30], two chemokines highly expressed in SS tissues and able to chemoactract SS cells in vitro [23, 37] prompted us to investigate in detail this mechanism.