| No staining | = | Grade 0 |
| Cellular staining between 0-25% | = | Grade 1 |
| Cellular staining between 25%- 50% | = | Grade 2 |
| Cellular staining between 50%- 75% | = | Grade 3 |
| Cellular staining between 75%- 100% | = | Grade 4 |
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