Altogether, it is concluded that S67 and S76 of the three serines involved in the degradation mechanism of PDCD4-protein, are phosphorylated by S6K1 activated via EGF-induced PI3K-Akt-mTOR-S6K1 signaling pathway and S71 and S76 may be phosphorylated independently from the phosphorylation of S67 by TPA mediated signaling pathway in Huh7 hepatoma cells (Figure 7). The gene discussed is PDCD4; the disease is hepatocellular carcinoma.