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Table 2 Differences in characteristics between two types of breast cancer classified by hormone receptor status

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+/HR+, n=28 (n=22) HER2+/HR-, n=18 (n=16) P-value
Response to neoadjuvant chemotherapy    
 pCR (grade 3) 8 (8) 12 (11) 0.009 (0.034)
 No pCR (grade 0–2) 14 (9) 3 (2)  
HER2 copy numbers    
 ≤ 2.0 6 2 0.368
 > 2.0 22 16  
Wild-type HER2 mRNA    
 < 400 16 (13) 7 (5) 0.05 (0.044)
 ≥ 400 7 (7) 11 (11)  
ΔHER2 mRNA    
 < 4.5 16 (13) 3 (2) <0.001 (0.001)
 ≥ 4.5 7 (7) 15 (14)  
Percentages of ΔHER2 mRNA    
 < 2.4% 20 (18) 15 (14) 0.745 (0.813)
 ≥ 2.4% 3 (2) 3 (2)  
PI3KCA (exons 9 and 20)    
 Wild-type 24 (19) 16 (14) 0.755 (0.418)
 Mutated 4 (1) 2 (2)  
PI3KCA (exons 9 and 20)    
 Wild-type + Normal + Loss + UPD 19 (18) 12 (12) 0.933 (0.611)
 Mutated + Gain 9 (4) 6 (4)  
PTEN    
 Normal + Gain + UPD 23 (20) 18 (16) 0.058 (0.215)
 Loss 5 (2) 0 (0)  
INPP4B    
 Normal + Gain + UPD 24 (20) 16 (14) 0.755 (0.735)
 Loss 4 (2) 2 (2)  
PI3KCA , PTEN, INPP4B    
 No aberrations* 15 (15) 10 (9) 0.895 (0.452)
 Aberrations** 13 (7) 8 (7)  
DEK    
 Normal 19 (17) 11 (11) 0.639 (0.556)
 Gain 9 (5) 7 (5)  
FGFR1    
 Normal + Loss + UPD 18 (15) 13 (12) 0.575 (0.871)
 Gain 10 (7) 5 (4)  
CCND1    
 Normal + Loss 16 (13) 9 (8) 0.635 (0.578)
 Gain 12 (9) 9 (8)  
FOXA1    
 Normal + UPD 20 (18) 13 (11) 0.953 (0.35)
 Gain 8 (4) 5 (5)  
CDH3    
 Normal + Loss + UPD 23 (19) 18 (16) 0.058 (0.124)
 Gain 5 (3) 0 (0)  
BIRC5    
 Normal + Loss + UPD 22 (17) 8 (6) 0.018 (0.013)
 Gain 6 (5) 10 (10)  
MYBL2    
 Normal + Loss 18 (15) 14 (13) 0.332 (0.366)
 Gain 10 (7) 4 (3)  
AIB1    
 Normal + Loss 19 (15) 14 (13) 0.466 (0.366)
 Gain 9 (7) 4 (3)  
  1. Numbers in parentheses indicate patientsΔ numbers excluding 6 HER2+/HR+ and 2 HER2+/HR- patients whose tumors had HER2 copy numbers ≤ 2.0, and P-values calculated from the numbers in the parentheses.
  2. *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.