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

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