Table 2 EGFR FISH classification system adapted from Varella-Garcia [35]
Tumour classification | EGFR status |
|---|---|
Disomy: ≤2 copies in ≥90 % cells | Negative |
Low trisomy: ≤2 copies in ≥40 % cells, 3 copies in 10-40 % cells, : ≤4 copies in <10 % cells | Negative |
High trisomy: ≤2 copies in ≥40 % cells, 3 copies in ≥40 % cells, : ≤4 copies in <10 % cells | Negative |
Low polysomy: ≥4copies in 10-40 % cells | Negative |
High polysomy: ≥4copies in ≥40 % cells | Positive |
Amplification: Any of | Positive |
-EGFR/CEP7 ratio ≥2 | |
- Small cluster (4-10 copies) or innumerable tight clusters in >10 % cells | |
- Larger and brighter EGFR signals v CEP7 signals in >10 % cells, with EGFR smaller than CEP7 in adjacent non-tumour cells | |
- >15 copies of EGFR signal in >10 % tumour cells INDEPENDANT of EGFR/CEP7 ratio | |
If amplified, pattern of amplification: | |
- Homogenous staining region (HSR) | |
- Double minute (DM) | |
- Heterogeneous amplification (HA) |