PTGS2 and cancer: As an increase in the levels of COX-2 mRNA and protein are found in most CRC compared to the normal surrounding mucosa and the development of this type of cancer is linked to an overexpression of this enzyme [254], there has been extensive research about inhibiting COX-2 function by NSAIDs or COX-2 inhibitors (COXIBs) to control CRC development during the last few decades (Figure 5).