The Gleason score from a prostate biopsy matches the final score from a radical prostatectomy about 60% to 75% of the time,

Upgrading (Higher score at surgery): The final pathology specimen shows a higher, more aggressive Gleason score than the initial biopsy in about 20% to 35% of cases. This often happens when a biopsy needle misses the most aggressive part of a tumor.
https://www.cancer.org/cancer/diagnosis-staging/tests/pathology-reports/prostate-pathology/prostate-cancer-pathology.html
Downgrading (Lower score at surgery): The final pathology shows a lower Gleason score than the biopsy in less than 5% to 10% of cases.
https://pmc.ncbi.nlm.nih.gov/articles/PMC4939641/