gleason Definition

a grade given to each of the two most prevalent patterns of cancer cells in tissue obtained from biopsy of a prostate tumor that is based on a scale of 1 to 5 with 1 to 3 corresponding to well-differentiated cancer cells similar in appearance to normal cells in surrounding tissue and 4 to 5 corresponding to poorly differentiated cancer cells that look abnormal

gleason score

a score that is the sum of the two Gleason grades assigned to a prostate tumor and that is based on a scale of 2 to 10 with the lowest numbers indicating a slow-growing tumor unlikely to spread and the highest numbers indicating an aggressive tumor