A previous study showed that over-expression of CAT-1 in HCC cells increased intracellular arginine levels and contributed to hepatocytogenesis, while knockdown of CAT-1 and miR122 together prevented an increase in intracellular NO; these results indicated that reduced miR-122 were a result of increased CAT-1 levels [24]. This evidence concerns the gene SLC7A1 and hepatocellular carcinoma.