Table 1.
Characteristic | All cases, number (%) | Centrally evaluated HER2- positive cases, number (%) |
Centrally evaluated HER2- negative cases, number (%) |
---|---|---|---|
Samples, number | 217 | 158 | 59 |
Local HER2 status (IH/ISH) | |||
positive | 217 (100) | 158 (100) | 59 (100) |
negative | 0 (0) | 0 (0) | 0 (0) |
Central HER2 status (IH/SISH) | |||
Positive | 158 (72.8) | 158 (100) | 0 (0) |
Negative | 59 (27.2) | 0 (0) | 59 (100) |
HER2 protein expression (central IH) | |||
3+ | 144 (66.4) | 144 (91.1) | 0 (0) |
2+ | 20 (9.2) | 8 (5.1) | 12 (20.3) |
0/1+ | 48 (22.1) | 2 (1.3) | 46 (78.0) |
missing | 5 (2.3) | 4 (2.5) | 1 (1.7) |
HER2 gene amplification (central SISH) | |||
SISH positive (>2.2) | 109 (50.2) | 109 (69.0) | 0 (0) |
SISH negative (<1.8) | 49 (22.6) | 10 (6.3) | 39 (66.1) |
SISH equivocal (1.8-2.2) | 8 (3.7) | 6 (3.8) | 2 (3.4) |
missing | 51 (23.5) | 33 (20.9) | 18 (30.5) |
HER2 mRNA expression (central qPCR) | |||
Positive (>19.5) | 141 (65.0) | 137 (86.7) | 4 (6.8) |
Negative (≤19.5) | 76 (35.0) | 21 (13.3) | 55 (93.2) |
ER/PR Status (local IH) | |||
ER+ and/or PR+ | 125 (57.6) | 84 (53.2) | 41 (69.5) |
ER-/PR- | 92 (42.4) | 74 (46.8) | 18 (30.5) |
ESR1 mRNA expression (central qPCR) | |||
Positive (>13.8) | 109 (50.2) | 70 (44.3) | 39 (66.1) |
Negative (≤13.8) | 108 (49.8) | 88 (55.7) | 20 (33.9) |
Tumor grade | |||
G1 to G2 | 114 (55.1) | 78 (49.4) | 36 (61.0) |
G3 | 93 (44.9) | 72 (45.6) | 21 (35.6) |
Missing | 10 (4.6) | 8 (5.1) | 2 (3.4) |
Clinical tumor stage | |||
cT1 to cT2 | 155 (71.4) | 110 (69.6) | 45 (76.3) |
cT3 to cT4 | 62 (28.6) | 48 (30.4) | 14 (23.7) |
Clinical nodal status | |||
cN0 | 83 (38.2) | 61 (38.6) | 22 (37.3) |
cN+ | 134 (61.8) | 97 (61.4) | 37 (62.7) |
Pathological response | |||
No pCR | 131 (60.4) | 84 (53.2) | 47 (79.7) |
pCR (ypT0/is ypN0) | 86 (39.6) | 74 (46.8) | 12 (20.3) |
Age group | |||
≤ 50 years | 109 (50.2) | 84 (53.2) | 25 (42.4) |
> 50 years | 108 (49.8) | 74 (46.8) | 34 (57.6) |
Tumor type | |||
Ductal/other | 207 (95.4) | 156 (98.7) | 51 (86.4) |
Lobular | 10 (4.6) | 2 (1.3) | 8 (13.6) |
HER2, human epidermal growth factor receptor 2; SISH, silver in situ hybridization; IH: immunohistochemistry; ISH: in situ hybridization; qPCR, quantitative polymerase chain reaction; ypT: tumor stage after neoadjuvant therapy; ypN: nodal status after neoadjuvant therapy.