Table 1.
Scoring systems for HER2
| HER2 IHC Scoring | ||
|---|---|---|
| Score |
Pre-ASCO/CAP Scoring Interpretation/Staining pattern |
ASCO/CAP Scoring Interpretation/Staining pattern |
| 0 | Negative/No staining Staining in < 10% of tumor cells |
Negative/No staining Staining in <10% of tumor cells |
| 1+ | Negative/Faint/barely perceptible incomplete membrane staining in >10% of tumor cells |
Negative/Faint/barely perceptible incomplete membrane staining in >10% of tumor cells |
| 2+ | Weakly positive/Weak to moderate complete membrane staining in >10% of tumor cells |
Equivocal/Weak to moderate complete membrane staining in >10% of tumor cells |
| 3+ | Strongly positive/Strong complete membrane staining in >10% of tumor cells |
Positive/Strong complete membrane staining in >30% of tumor cells |
| HER2 FISH Scoring | ||
|
Pre-ASCO/CAP Scoring Interpretation/Ratio (HER2/CEP17) |
ASCO/CAP Scoring Interpretation/Ratio (HER2/CEP17) |
|
| Negative/<2.0 | Negative/< 1.8 | |
| Equivocal/1.8-2.2 | ||
| Positive/>= 2.0 | Positive/> 2.2 | |
HER2 human epidermal growth factor receptor 2; IHC immunohistochemistry; FISH fluorescence in situ hybridization; ASCO American Society of Clinical Oncology; CAP College of American Pathologists; CEP17 chromosome enumeration probe 17 (probe for the centromer of chromosome 17)