Given that the Rac1-p-MLC signal had been reported to play an important role in cell motility by promoting the contractile motion of the myosin light chain, we used interruption approaches with a specific inhibitor to block Rac1 (100 μM, NSC 23766, MedChemExpress, Monmouth Junction, NJ), we found that the cell migration was suppressed in HNSCC cells treated with CCL2 (Fig. 3A, B). This evidence concerns the gene RAC1 and head and neck squamous cell carcinoma.