In hepatocellular carcinoma, celecoxib acted synergistically with chemotherapeutic drugs in promoting apoptosis, and celecoxib induced COX-2 inhibition in different apoptotic pathways, including stimulating death receptor signaling, activation of caspases and mitochondrial apoptosis pathway (Kern et al., 2006). Here, PTGS2 is linked to hepatocellular carcinoma.