Table 8. Concordance between IHC and endpoint RT-PCR based on ER, PR, and HER2 status.
| Variables | Concordance | ||||
|---|---|---|---|---|---|
| OPA | PPA | NPA | κ value | P-value | |
| ER | 68.3 (28/41) | 71.1 (27/38) | 33.3 (1/3) | 0.018 (< 0.20) | > 0.05 |
| PR | 39.0 (16/41) | 14.3 (4/24) | 92.3 (12/13) | 0.045 (< 0.20) | > 0.05 |
| HER2 | 82.9 (34/41) | 62.5 (5/8) | 87.9 (29/33) | 0.481 (0.41-0.60) | < 0.05 |
Values are presented as % (number/number). IHC, immunohistochemistry; OPA, overall percent agreement; PPA, positive percent agreement; NPA, negative percent agreement; RT-PCR, reverse transcription PCR; ER, estrogen receptor; PR, progesterone receptor; HER2, human epidermal growth factor receptor 2.