Table 5.
Comparison of immunohistochemistry using various ALK antibodies and fluorescence in situ hybridization
| Mayo study: IHC (ALK1) versus FISH study (κ = 0.55)37 (12 ALK FISH positives out of 103 NSCLC tumors screened) | ||||
|---|---|---|---|---|
| IHC 3+ (n = 8) | IHC 2+ (n = 4) | IHC 1+ (n = 22) | IHC 0 (n = 69) | |
| ALK FISH-positive (n = 12) | 8 | 3 | 1 | 0 |
| ALK FISH-negative (n = 91) | 0 | 1 | 21 | 69 |
| Seoul National University study: IHC (5A4) versus FISH study (κ = 0.92)38 (28 ALK FISH positives out of 640 screened) | ||||
| IHC 3+ (n = 16) | IHC 2+ (n = 10) | IHC 1+ (n = 14) | IHC 0 (n = 413) | |
| Test set (19 ALK FISH positives out of 453 tumors screened) | ||||
| ALK FISH-positive (n = 19) | 16 | 3 | 0 | 0 |
| ALK FISH-negative (n = 434) | 0 | 7 | 14 | 413 |
| IHC 3+ (n = 6) | IHC 2+ (n = 6) | IHC 1+ (n = 2) | IHC 0 (n = 173) | |
| Validation set (9 ALK FISH out of 187 tumors screened) | ||||
| ALK FISH-positive (n = 9) | 6 | 3 | 0 | 0 |
| ALK FISH-negative (n = 178) | 0 | 3 | 2 | 173 |
Abbreviations: ALK, anaplastic lymphoma kinase; κ, interobserver variability; FISH, fluorescence in situ hybridization; IHC, immunohistochemistry; NSCLC, non-small cell lung cancer.