Table 3 Prevalence of molecular phenotypes by IHC and PAM50 intrinsic subtype

From: PAM50 gene signatures and breast cancer prognosis with adjuvant anthracycline- and taxane-based chemotherapy: correlative analysis of C9741 (Alliance)

Variable

Basal-like (N=293)

HER2-E (N=266)

LumA (N=414)

LumB (N=338)

IHC subtype a

 Unknown

64

53

118

52

 ER− HER2−

161 (70%)

85 (40%)

15 (5%)

8 (3%)

 ER− HER2+

50 (22%)

27 (13%)

11 (4%)

5 (2%)

 ER+ HER2−

14 (6%)

80 (38%)

208 (70%)

214 (75%)

 ER+ HER2+

4 (2%)

21 (10%)

62 (21%)

59 (21%)

Ki67

 Unknown

60

54

111

44

 Neg. (<13.5%)

67 (29%)

112 (53%)

291 (96%)

202 (69%)

 Pos. (13.5%)

166 (71%)

100 (47%)

12 (4%)

92 (31%)

CK5/6

 Unknown

61

52

121

47

 0

75 (32%)

121 (57%)

225 (77%)

231 (79%)

 1

99 (43%)

88 (41%)

61 (21%)

60 (21%)

 2

58 (25%)

5 (2%)

7 (2%)

1 (0%)

EGFR

 Unknown

56

48

101

39

 0

76 (32%)

161 (74%)

297 (95%)

288 (96%)

 1

118 (50%)

41 (19%)

13 (4%)

10 (3%)

 2

43 (18%)

16 (7%)

3 (1%)

1 (0%)

  1. Abbreviations: CK, cytokeratin; EGFR, epidermal growth factor receptor; HER2-E, HER2-enriched; IHC, immunohistochemistry; Lum, luminal; Neg., negative; Pos., positive.
  2. Column percentages are computed excluding samples with unknown status by IHC.
  3. a ER-positivity is defined by ≥1% positive tumor nuclei. HER2-positivity is defined by staining of >50% carcinoma cells.