Table 3 UCCC scoring and interpretation of different types of EGFR gene amplification in NSCLC specimens.
Pattern Description | Scoring Criteria | Number of Cells to Score | Expected Ratio Gene to Chromosome | FISH result* |
|---|---|---|---|---|
Large, loose clusters of red (EGFR) signals | Count signals thoroughly and calculate the FISH indexes | 30 | >2 | GA |
Small, loose clusters of red (EGFR) signals | Count signals thoroughly and calculate the FISH indexes | 30 | >2 or ~1 if high level of aneusomy 7 is present | GA if ratio >2 GA if clusters are present in >10% cells, independent of ratio |
Large, loose co-localized clusters of red (EGFR) and green (CEP 7) signals | Count signals thoroughly, account for the innumerable signals using the symbol greater than (>) in front of the final counting | 30 | ~1 | GA if clusters are present in >10% cells |
Tightly packed, innumerable cluster of red (EGFR) signals or atypically large red (EGFR) signal, consistently bigger than the green (CEP 7) signal in the tumor cells but smaller in the adjacent stromal and reactive cells | Count signals in at least 50 cells and identify each cell displaying this specific feature in the analysis sheet | ≥ 50 | ~1 | GA if tight clusters or atypical red signal is present in >10% cells |
EGFR as double minutes | Count signals thoroughly and calculate the FISH indexes | 30 | >2 | GA |
Very high number of balanced red (EGFR) and green (CEP 7) signals | Count signals in at least 50 cells | ≥50 | ~1 | GA if >10% cells have ≥ 15 red (EGFR) signals |