PTGS2 and cancer: Also, the expression of other proteins in the cancer-associated stroma, that is, hypoxia regulated proteins (Cleven et al, 2007), matrix degrading proteases (Hilska et al, 2007) and cyclooxygenase-2 (Sonoshita et al, 2002; Adegboyega et al, 2004), is correlated to CRC progression and disease prognosis.