RPS6 and neoplasm: Using a conditional approach to delete the Rps6 gene in hepatoblasts of the embryonic liver or mature hepatocytes of the adult liver, we show that Rps6 is required for establishing and maintaining hepatic homeostasis and that during the perinatal period, a significant reduction, but not total loss of Rps6 is sufficient to induce a ribosomopathy-like phenotype that manifests as severe neonatal hepatic hypoplasia and cholestasis with a predisposition for tumor development.