Table 7.
Classification of HER2 Overexpression of the Discovery and Validation Sets Using the ΔΔCT Cutoff-Point and Clustering Methods
| Discovery (n = 55) |
Validation (n = 272) |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| ΔΔCTcutoff-point |
Clustering |
ΔΔCTcutoff-point |
Clustering |
|||||||
| HER2 IHC scorea | IHC (% of total) | HER2-over | HER2-norm | HER2-over | HER2-norm | IHC (% of total) | HER2-over | HER2-norm | HER2-over | HER2-norm |
| 0 | 10 | 0 | 10 | 0 | 10 | 200 | 2 | 198 | 0 | 200 |
| 1+ | 20 | 0 | 20 | 0 | 20 | 53 | 2 | 51 | 0 | 53 |
| 2+ | 8 | 1 | 7 | 0 | 8 | 2 | 0 | 2 | 0 | 2 |
| HER2-norm* | 38 (69%) | 1 | 37 | 0 | 38 | 255 (94%) | 4 | 251 | 0 | 255 |
| 3+ | 17 | 13 | 4 | 8 | 9 | 17 | 14 | 3 | 5 | 12 |
| HER2-over† | 17 (31%) | 13 | 4 | 8 | 9 | 17 (6%) | 14 | 3 | 5 | 12 |
*
Total number of specimens with HER2 IHC scores 0, 1+, and 2+.
†
The number of specimens with HER2 IHC score 3+.