HER2 status in operable breast cancers from Vietnamese women: Analysis by immunohistochemistry (IHC) and automated silver enhanced in situ hybridization (SISH)

Figures & data

Table I. Clinicopathology features.

Variables	n	%
Menopausal status
Pre	156	65
Post	83	34
unknown	3	1
Tumor size
≤2 cm	38	16
>2 cm	197	81
unknown	7	3
Lymph node metastasis
Negative	136	56
Positive	105	44
unknown	1
Pathology type
Ductal invasive	217	90
Lobular invasive	11	4
Others	14	6
Tumor grade
I + II	184	85
III	27	12
unknown	6	3
ER status
Positive	151	62
Negative	91	38
PgR status
Positive	112	47
Negative	129	53
unknown	1
HER2 protein expression
0	84	35
1+	36	15
2+	28	11
3+	94	39

Table II. Concordance between HER2 status as assessed by SISH and by IHC.

		IHC
		2+	3+
SISH testing	Non-amplification	14	4
	Equivocal	0	1
	Amplification	12	88
	Total	26	93

The overall agreement between two methods in this study is 87%.

Table III. Association of HER2 gene amplification with clinicopathological parameters.

	SISH
Parameters	Negative n (%)	Positive n (%)	OR (p-value)
Age
≤50	97 (65)	53 (35)	2.1 (0.006)
>50	41 (47)	47 (53)
Menopause
Pre	98 (64)	55 (36)	2.2 (0.005)
Post	37 (45)	45 (55)
Tumor stage
≤T1	21 (55)	17 (45)	0.93 (0.84)
>T1	110 (57)	83 (43)
Histo-pathology
Ductal carcinoma	120 (56)	94 (44)	2.3 (0.07)
Others	18 (75)	6 (25)
Tumor grade
III	17 (63)	10 (37)	0.68 (0.36)
I, II	97 (54)	84 (46)
Lymph node
(+)	59 (57)	44 (43)	1.0 (0.85)
(−)	79 (59)	56 (41)
ER status
ER (−)	38 (43)	50 (57)	2.6 (0.0004)
ER (+)	100 (67)	50 (33)
PR status
PgR (−)	60 (47)	67 (53)	2.6 (0.0004)
PgR (+)	77 (70)	33 (30)

Table IV. HER2 amplification in breast cancers from Vietnamese and Swedish women (%).

	Vietnamese (n = 242)	Swedish (n = 2225)	P-value
All patients	41	13	<0.001
Premenopausal	36	16	<0.001
Postmenopausal	55	12	<0.001
ER positive	33	9	<0.001
ER negative	57	31	<0.001