Table 1: The Current CAP protocol for prostate cancer grading and Gleason score standard.

Grade group Gleason score Definition
1 Less than or equal to 6 Only individual discrete well-formed glands
2 3 + 4 = 7 Predominantly well-formed glands with lesser component of poorly formed/fused/cribriform glands
3 4 + 3 = 7 Predominantly poorly formed/fused/cribriform glands with lesser component (#) of well-formed glands
4 4 + 4 = 8 Only poorly formed/fused/cribriform glands
3 + 5 = 8 Predominantly well-formed glands and lesser component (##) lacking glands (or with necrosis)
5 + 3 = 8 Predominantly lacking glands (or with necrosis) and lesser component (##) of well-formed glands
5 9 - 10 Lack gland formation (or with necrosis) with or without poorly formed/fused/cribriform glands (#)