XDH and cancer: MS also increases the risk of developing cancer, namely by being correlated with an increase in xanthine oxidoreductase activity, causing higher formations of reactive oxygen species (ROS) and uric acid, which in turn causes an upregulation of the renin/angiotensin pathway and an increase in cyclooxygenase-2 (COX-2) expression [7]; therefore, increased xanthine oxidoreductase activity is correlated with MS and cancer development.