Abstract:【Abstract】 Objective To study the effect of tumor necrosis factor related receptor factor 6 (Traf6) on the proliferation of breast cancer MCF7 cells and its possible mechanism. Methods The qualified recombinant plasmid shTraf6pGPU6/Neo was transfected into MCF7 cells to knock down Traf6 related gene. The level of Traf6 was detected on both mRNA and protein levels by realtime PCR and Western blot. CCK8 assay and flow cytometry were performed to detect the change of proliferation and cell cycle in MCF7 cells. The expression of cell cycle associated proteins (Cyclin A, Cyclin B and CDK/p34) and TAK phosphorylation were also detected and recorded. Results The Traf6 plasmid was constructed successfully. MCF7 cells with Traf6 knocking down had been established successfully. Knocking down of Traf6 inhibited the proliferation of MCF7 significantly, stimulated the apoptosis of MCF7 cells, and cells were blocked in G1phase. Moreover, the Traf6 knock out increased the expression levels of cycle proteins (Cyclin A, Cyclin B and CDK/p34) and TAK1 phosphorylation. Conclusion Suppression of Traf6 can inhibit the proliferation and induce the apoptosis of MCF7 cells through TAK1 signaling pathway.