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Table 1 Differences in characteristics between two types of breast cancer classified by HER2 copy numbers

From: Alterations of the genes involved in the PI3K and estrogen-receptor pathways influence outcome in human epidermal growth factor receptor 2-positive and hormone receptor-positive breast cancer patients treated with trastuzumab-containing neoadjuvant chemotherapy

  HER2 copy number ≤ 2.0 (n=8) HER2 copy number > 2 (n=38) P-value
Hormone receptor status (n=46)    
 Positive 6 22 0.368
 Negative 2 16  
Response to neoadjuvant chemotherapy (n=37)    
 pCR (grade 3) 1 19 0.019
 No pCR (grade 0–2) 6 11  
Relapse after surgery (n=42)    
 Not occurred 3 27 0.018
 Occurred 5 7  
Wild-type HER2 mRNA (n=41)    
 < 400 5 18 0.035
 ≥ 400 0 18  
ΔHER2 mRNA (n=41)    
 < 4.5 4 15 0.107
 ≥ 4.5 1 21  
Percentages of ΔHER2 mRNA (n=41)    
 < 2.4% 3 32 0.087
 ≥ 2.4% 2 4  
PI3KCA (exons 9 and 20) (n=46)    
 Wild-type 5 35 0.024
 Mutated 3 3  
PI3KCA (exons 9 and 20) (n=46)    
 Wild-type + Normal + Loss + UPD 2 29 0.005
 Mutated + Gain 6 9  
PTEN (n=46)    
 Normal + Gain + UPD 5 36 0.008
 Loss 3 2  
INPP4B (n=46)    
 Normal + Gain + UPD 6 36 0.072
 Loss 2 2  
PI3KCA , PTEN, INPP4B (n=46)    
 No aberrations* 1 24 0.009
 Aberrations** 7 14  
DEK (n=46)    
 Normal 3 27 0.07
 Gain 5 11  
FGFR1 (n=46)    
 Normal + Loss + UPD 4 27 0.248
 Gain 4 11  
CCND1 (n=46)    
 Normal + Loss 4 21 0.786
 Gain 4 17  
FOXA1 (n=46)    
 Normal + UPD 4 29 0.133
 Gain 4 9  
CDH3 (n=46)    
 Normal + Loss + UPD 6 35 0.158
 Gain 2 3  
BIRC5 (n=46)    
 Normal + Loss + UPD 6 23 0.441
 Gain 2 15  
MYBL2 (n=46)    
 Normal + Loss 4 28 0.186
 Gain 4 10  
AIB1 (n=46)    
 Normal + Loss 5 28 0.523
 Gain 3 10  
  1. *No aberrations, wild-type and a normal copy of PIK3CA, a normal copy, gain or UPD of PTEN or INPP4B; **Aberrations, mutated and/or gain of PIK3CA, and loss of PTEN or INPP4B.