TSC1 and hepatocellular carcinoma: Last, ARG1 was reported to promote HCC growth and metastasis by enhancing tumor cell epithelial-mesenchymal transition (31), whereas ectopic expression of ARG1 in a Tsc1/Pten DKO model suppressed HCC development by consuming arginine (32), and limiting arginine led to tumor cell growth arrest and apoptosis (22).