RPS6 and neoplasm: Although p70S6K and its substrate ribosomal protein S6 are also known as regulators of mRNA biogenesis and translation, a growing body of evidence, including our studies, indicate that the deregulation of cap-dependent translation downstream of mTORC1 at the level of 4E-BP1/eIF4E plays a central role in tumor formation and metastatic progression; the contribution of p70S6K1 and S6 to the oncogenic action of the mTORC1 upstream activators, AKT and/or extracellular signal-regulated kinase, appears limited [12, 27, 39, 40].