Previously, we have demonstrated that CPT could down-regulate expression of cyclin D1 and Rb protein and lead to cancer cell arrested in G0 phase [14], which is mainly mediated by inhibition of mTORC1 because the best-characterized effectors downstream of mTORC1, S6K1 and 4EBP1 were dephosphorylated. This evidence concerns the gene RPS6KB1 and cancer.