Table 3. Prevalence of molecular phenotypes by IHC and PAM50 intrinsic subtype.
| Variable | Basal-like (N=293) | HER2-E (N=266) | LumA (N=414) | LumB (N=338) |
|---|---|---|---|---|
|
IHC subtypea | ||||
| 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%) |
Abbreviations: CK, cytokeratin; EGFR, epidermal growth factor receptor; HER2-E, HER2-enriched; IHC, immunohistochemistry; Lum, luminal; Neg., negative; Pos., positive.
Column percentages are computed excluding samples with unknown status by IHC.
a
ER-positivity is defined by ≥1% positive tumor nuclei. HER2-positivity is defined by staining of >50% carcinoma cells.