A good Gleason score is between 2 and 4, according to WebMD. A Gleason score indicates how much a prostate biopsy resembles normal prostate tissue. The scale runs from 2 to 10, with lower scores suggesting that a prostate tumor is not likely to grow quickly.
A tumor with a Gleason score between 8 and 10 looks very little like normal tissue, states WebMD. This type of cancer is expected to spread fast. Prostate tissue that scores between 5 and 7 has a moderate risk factor. A pathologist reaches a Gleason score for a tissue sample by determining the two most common tumor patterns in the biopsy. Each is graded from 1 to 5, and then the numbers are added.