MTOR and cancer: The recovery of a subset of the known elements crucial for S6 phosphorylation together with the significant enrichment of the confirmed “S6-positives” among the genes whose essentiality parallels that of mTOR in a large cohort of cancer cell lines supports the view that the 642 genes identified in the primary screen for regulators of S6 phosphorylation are in fact enriched in regulators of mTOR complex 1.