Gleason score was revised in 2005 by International Society of Urological Pathology (ISUP). This revision has great impacts on prostate cancer diagnosis and treatment. However, some issues were not reached to consensus. In addition, some modifications are needed to adapt recent advanced prostate cancer therapies, especially for patients with active surveillance and very high risk prostate cancer. The authors review recently updated Gleason grading system by ISUP, which will fit to recent prostate cancer treatment. There are few prognostic factors to predict cancer specific survival and overall survival. The authors show the concept and diagnostic criteria of IDC-P. The authors also discuss clinical usefulness and problems of IDC-P in practice.