Table 3. Correlations of EGFR GCN (SISH), Chr-7 number (SISH), KRAS status and EGFR protein expression (IHC), n=74 (P-values, Spearman).
| KRAS status | EGFR GCN (SISH) continuous variable | Chr-7 (SISH) continuous variable | |
|---|---|---|---|
| Anti-EGFR clone 5B7, intensity | |||
| Highest† | NS | 0.01* | 0.01* |
| Most common† | NS | NS | NS |
| Positive or negative≠ | NS | 0.01* | 0.04* |
| Anti-EGFR clone 3C6, intensity | |||
| Highest† | NS | NS | 0.04* |
| Most common† | NS | NS | NS |
| Positive or negative≠ | NS | NS | NS |
| Localisation | |||
| 5B7§ | NS | NS | NS |
| 3C6§ | NS | NS | NS |
| EGFR GCN (SISH) | |||
| Continuous variable | NS | — | <0.0001* |
| Cut-off 4.0 | NS | — | — |
| Chr-7 number (SISH) | |||
| Continuous variable | NS | <0.0001* | — |
| Cut-off 4.5 | NS | — | — |
Abbreviations: Chr-7=chromosome-7; EGFR=epidermal growth factor receptor; GCN=gene copy number; IHC=immunohistochemistry; NS=not significant; SISH=silver in situ hybridisation; *Significant P-value; †0, 1+, 2+, or 3+ ≠Positive 2+ or 3+, negative 0, or 1+ §Membranous, cytoplasmic, both cytoplasmic and membranous or negative.