Objective:To investigate the signal pathway of EGF and TGF-α modulating the distribution of cell cycle in tongue squamous cell. Methods:Flow cytometric analysis and immunohistochemistry were employed to investigate the cell cycle distribution,and expressed levels of p38-MAP kinase,c-myc,c-fos and NF-κB respectively. Results:EGF and TGF-α showed similar effect on tongue squamous cell,but the dose-effect relationships were different. In comparison with the control,the proportion of cells in G1/G0 declined and that in S phase ascended. The levels of p38-MAP kinase,c-myc and c-fos were down-regulated and NF-κB p65 up-regulated. EGF and TGF-α up- and down-regulated the expressed levels of NF-κB p50 respectively. Conclusion:The distinct expression of NF-κB may be one of the reasons that results in the difference of EGF and TGF-α on the cell cycle distribution. NF-κB is closely related to the occurrence of tongue squamous carcinoma.