AREG and neoplasm: Eight genes were downregulated after S6K1 silencing, but upregulated after S6K2 knock-down, among these the EGFR ligand amphiregulin (AREG), the glutamate-ammonia ligase (GLUL) involved in glutamine synthesis, and the CDK5 and ABL1 enzyme substrate 1 (CABLES1), implicated as a tumour suppressor [38].