|  | HER2 status by RT-PCR | Concordancea | Positive concordance and negative concordance | |||
---|---|---|---|---|---|---|---|
 |  | Negative | Equivocal | Positive | Total | ||
n (%) | n (%) | n (%) | n (%) | Â | |||
Central HER2 IHC | 0 | 14 (1.6) | 1 (0.1) | 1 (0.1) | 16 (1.8) | 87.6 % | Pos. concordance = 87.8 % |
1+ | 19 (2.1) | 6 (0.7) | 0 (0.0) | 25 (2.8) | Neg. concordance = 86.6 % | ||
2+ | 58 (6.5) | 25 (2.8) | 18 (2.0) | 101 (11.2) | |||
(Ref = IHC) | |||||||
3+ | 39 (4.3) | 53 (5.9) | 664 (73.9) | 756 (84.2) | |||
 | Total | 130 (14.5) | 85 (9.5) | 683 (76.1) | 898 | ||
 |  | HER2 status by RT-PCR |  | 84.4 % | Pos. concordance = 83.8 % | ||
 |  | Negative | Equivocal | Positive | Total | ||
n (%) | n (%) | n (%) | n (%) | Neg. concordance = 89.8 % | |||
Central HER2 FISH ratio | <2 | 62 (7.0) | 17 (1.9) | 9 (1.0) | 88 (10.0) | (Ref = FISH) | |
≥2 | 64 (7.2) | 65 (7.4) | 667 (75.5) | 796 (90.0) | |||
 | Total | 126 (14.3) | 82 (9.3) | 676 (76.5) | 884 | ||
 |  | Central HER2 FISH ratio |  | 85.8 % | Pos. concordance = 88.9 % (Ref = FISH) | ||
 |  | <2 | ≥2 | Total | |||
n (%) | n (%) | n (%) | |||||
Central HER2 IHC | 0 | 14 (1.6) | 2 (0.2) | 16 (1.8) | |||
1+ | 14 (1.6) | 10 (1.1) | 24 (2.7) | Neg. concordance = 58.0 % (Ref = FISH) | |||
2+ | 23 (2.6) | 76 (8.6) | 99 (11.2) | ||||
3+ | 37 (4.2) | 706 (80.0) | 743 (84.2) | ||||
 | Total | 88 (10.0) | 794 (90.0) | 882 |