Table 1 Baseline clinicopathological characteristics of the cohort
Clinicopathological characteristics | Total (n=523); n(%) | IHC/FISH-based HER2 status subgroup; n(%) | |||
|---|---|---|---|---|---|
HER2-zero (n=90) | HER2-low (n=231) | HER2-positive (n=202) | p-value | ||
Age (median [range], years) | 48 [25-85] | 46[25-85] | 49[27-76] | 49.5[27-74] | ns |
Menopausal status | |||||
 Pre-menopause | 297(56.8%) | 56(62.2%) | 131(56.7%) | 110(54.5%) | ns |
 Post-menopause | 226(43.2%) | 34(37.8%) | 100(43.3%) | 92(45.5%) | |
Tumor (T) stage | |||||
 T1-T2 | 469(89.7%) | 80(88.9%) | 208(90.0%) | 181(89.6%) | ns |
 T3-T4 | 51(9.7%) | 8(8.9%) | 22(9.5%) | 21(10.4%) | |
 Unknown | 3(0.6%) | 2(2.2%) | 1(0.5%) | 0 | |
Lymph node (N) stage | |||||
 N0-N1 | 400(76.5%) | 68(75.6%) | 176(76.2%) | 156(77.2%) | ns |
 N2-N3 | 121(23.1%) | 20(22.2%) | 55(23.8%) | 46(22.8%) | |
 Unknown | 2(0.4%) | 2(2.2%) | 0 | 0 | |
Metastasis (M) stage | |||||
 M0 | 495(94.6%) | 84(93.3%) | 226(97.8%) | 185(91.6%) | Zero vs Low, p =0.036 |
 M1 | 26(5.0%) | 4(4.4%) | 5(2.2%) | 17(8.4%) | Zero vs Positive, ns |
 Mx | 2(0.4%) | 2(2.2%) | 0 | 0 | Low vs Positive, p =0.004 |
Pathological stage | |||||
 I-II | 378(72.3%) | 65(72.2%) | 168(72.7%) | 145(71.8%) | ns |
 III-IV | 142(27.1%) | 23(25.6%) | 62(26.8%) | 57(28.2%) | |
 Unknown | 3(0.6%) | 2(2.2%) | 1(0.5%) | 0 | |
Histological grade | |||||
 1 | 13(2.5%) | 3(3.3%) | 8(3.5%) | 2(1.0%) | Zero vs Low, p <0.001 |
 2 | 248(47.4%) | 31(34.4%) | 137(59.3%) | 80(39.6%) | Zero vs Positive, ns |
 3 | 248(47.4%) | 50(55.6%) | 82(35.5%) | 116(57.4%) | Low vs Positive, p <0.001 |
 Unknown | 14(2.7%) | 6(6.7%) | 4(1.7%) | 4(2.0%) |  |
Histological type | |||||
 Invasive carcinoma of no special type (NST) | 483(92.4%) | 77(85.6%) | 214(92.6%) | 192(95.0%) | Zero vs Low, p =0.043 |
 Lobular, invasive | 15(2.9%) | 4(4.4%) | 10(4.3%) | 1(0.5%) | Zero vs Positive, p =0.008 |
 Other invasive histology | 25(4.7%) | 9(10.0%) | 7(3.1%) | 9(4.5%) | Low vs Positive, p =0.023 |
Estrogen Receptor (ER) status |  |  |  | Zero vs Low, p <0.001 | |
 Positive | 360(68.8%) | 59(65.6%) | 198(85.7%) | 103(51.0%) | Zero vs Positive, p =0.022 |
 Negative | 163(31.2%) | 31(34.4%) | 33(14.3%) | 99(49.0%) | Low vs Positive, p <0.001 |
Progesterone Receptor (PR) status |  |  |  | Zero vs Low, p <0.001 | |
 Positive | 335(64.1%) | 52(57.8%) | 191(82.7%) | 92(45.5%) | Zero vs Positive, ns |
 Negative | 188(35.9%) | 38(42.2%) | 40(17.3%) | 110(54.5%) | Low vs Positive, p <0.001 |
Hormone Receptor (HR) status |  |  |  | Zero vs Low, p <0.001 | |
 Positive | 380(72.7%) | 60(66.7%) | 202(87.4%) | 118(58.4%) | Zero vs Positive, ns |
 Negative | 143(27.3%) | 30(33.3%) | 29(12.6%) | 84(41.6%) | Low vs Positive, p <0.001 |
Ki67 expression level (median, IQR) | 30.0%[15.0%, 50.0%] | Â | Â | Â | Â |
Ki67 expression status (cut-off 30%) | Zero vs Low, p =0.013 | ||||
 Low (<30%) | 225(43.4%) | 38(42.2%) | 132(57.9%) | 55(27.5%) | Zero vs Positive, p =0.015 |
 High (≥30%) | 293(56.6%) | 52(57.8%) | 96(42.1%) | 145(72.5%) | Low vs Positive, p <0.001 |
Immunohistochemistry-based surrogate molecular subgrouping | |||||
 Luminal A (ER±/PR±/HER2-/Ki67<14%) | 91(17.4%) | 25(27.8%) | 66(28.6%) | 0 | Zero vs Low, p <0.001 |
 Luminal B HER2- (ER±/PR±/HER2-/Ki67≥14%) | 171(32.7%) | 35(38.9%) | 136(58.9%) | 0 | Zero vs Positive, p <0.001 |
 Luminal B HER2+ (ER±/PR±/HER2+/Ki67≥14%) | 118(22.6%) | 0 | 0 | 118(58.4%) | Low vs Positive, p <0.001 |
 HER2-enriched (ER-/PR-/HER2+) | 84(16.1%) | 0 | 0 | 84(41.6%) |  |
 Triple-negative (ER-/PR-/HER2-) | 59(11.3%) | 30(33.3%) | 29(12.6%) | 0 |  |