PTGS2 and hepatocellular carcinoma: To examine whether COX-2 expression is under the control of miRNAs, we determined the expression pattern of COX-2 and selected miRNAs in four hepatoma (HCC) cell lines (HepG2, PLC/PRF/5, HuH-7, Hep3B) and in a cell line derived from human liver embryo (WRL68), using human hepatocytes (HH) as control (Fig. 1A).