Association between HER2 genetic heterogeneity and other tumour characteristics in breast carcinomas with equivocal (2+) HER2 immunostaining (N=345)
| Variable | p Value (two-tailed) |
| Absence of HER2 gene cluster | 0.019 |
| Polysomy 17 (chromosome 17 copy number >2.25) | 0.010 |
| Age (<50 vs ≥50 years) | 0.463 |
| Size (≤2.0 vs >2.0 cm) | 0.807 |
| Histological type | 0.401 |
| Histological grade | 0.033 |
| Oestrogen receptor status (positive vs negative) | 1.000 |
| Progesterone receptor status (positive vs negative) | 1.000 |
| Ki-67 labelling index (low vs high) | 0.276 |
| pT stage | 0.130 |
| Nodal status (positive vs negative) | 0.254 |
| SSI (stable vs unstable) | 1.000 |
| DNA ploidy category | 0.001 |
| 5c Exceeding rate (low vs high) | 0.005 |
SSI, stem line scatter index.