| |
Specimen |
IHC Positive (3+) |
FISH Positive |
| Breast* |
Biopsy |
Uniform, strong circumferential membrane staining in ≥ 30% of cells (chicken wire pattern) |
20 cohesive tumor cells showing
highest gene count (count
additional 20 if ratio 1.8-2.2)
HER2/CEP17 ratio ≥ 2.2 |
| |
Resection |
Same |
Same |
| Gastric** |
Biopsy |
≥ 5 Cells Moderate-strong complete basolateral or lateral only staining |
20 cohesive tumor cells showing highest gene count (count additional 20 if ratio 1.8-2.2) HER2/CEP17 ratio |
| |
Resection |
≥ 10% Cells Moderate-strong complete basolateral or lateral only staining |
20 cohesive tumor cells showing highest gene count (additional 20 if ratio 1.8-2.2) HER2/CEP17 ratio ≥ 2.0 HER2 signals > 6 |
*ASCO/CAP