PTGS2 and hepatocellular carcinoma: Initially, by RT-PCR, we found TPA elevated mRNA of SNA by 3.7-fold at 1 h and declined until 6 h, whereas it significantly increased mRNA of FN, LEF, and COX2 by 1.5–2-fold within 1–2 h, which was further increased to 2.5–4.8-fold until 6 h in HepG2, one of the conventional HCC cell lines (Figure 1a).