Patients with prostate cancer all know their "Gleason grade" or "Gleason score". The scoring system
was developed by Dr. Donald Gleason in the 1960s while he was at the Minneapolis VA. Dr. Gleason passed away late last year as recently reported. His scoring system has stood the test of time as a reliable indicator and predictor for clinical behavior to guide therapy, management & provide a standard as part of clinical trials.
While widespread adoption did not occur for many years after the scoring system was devised, 
it would be hard to find any
surgical pathologists who have not referenced this diagram at some point during their training or practice for accurate grading of prostate cancer.
Despite taking years to fully adopt and some minor adjustments to the scoring system and/or its use, Gleason scoring remains one of the most accurate, reproducible & widely used grading systems in cancer grading.
While the studies for the most part were performed on prostatectomy specimens, the system may be used accurately on smaller needle biopsies as well and limitations with smaller amounts of tissue on biopsy are well-known and are still accurate in terms of clinical decision making.
It will be interesting to see if computer assisted algorithms and scoring programs will be as accurate and clinically useful as Gleason's initial work and hand drawings to describe his findings. 
