NOS2 and prostate cancer: Similar to these studies, Aaltomaa et al searched for iNOS expression in 82 patients with local prostate cancer and there was weak or strong expression of iNOS in 25 (31%) and 56 (68%) of the patients but they also could not find any significant association with tumor grade and iNOS expression patern.26 These could be explained by the small number of groups and narrow range of Gleason scores.