PTGS2 and cancer: The levels of TIMP-1, COX-2 and MMP-7 in cancer tissues were higher than those of both normal tissue and polyp tissue (p = 0.009 and p = 0.001; p < 0.001 and p < 0.001; p = 0.029 and p = 0.008, respectively) (Tables 2 to 4).