Depending on the abnormality of the glands, a Gleason Score from 1-5 is assigned. The higher the value, the higher the degree of deterioration and the more aggressive the tumour is.

The assessment is based on material from prostate core biopsy or a surgically removed prostate. Here, the degree of deviation (from the normal tissue) of the first and second most frequent cell population of the tumour is evaluated.  The score is always assigned according to the following pattern: Gleason value 1 + value 2 = sum of both values

For example, the means at least 1 + 1 = 2 to a maximum of 5 + 5 = 10