Table 5 Key features of the protocols for comparison
Feature | PathVysion | PharmDx | INFORM | CISH |
|---|---|---|---|---|
Reagents | Preparation required | Ready to use | Ready to use | Ready to use |
Stability of reagents | pH requires checking | OK | OK | OK |
DAPI | Bright | Low intensity | Not provided | - |
Background | Orange fluorescence | Strong; green fluorescence | Faint; green fluorescence | - |
Stability of signal | Good | Rapid quenching of FITC signal | Good | Excellent |
HER2 probe | Spectrum Orange; clear signal but high background fluorescence | Texas red; strong clear signal | FITC; strong clear signal | Chromogenic; peroxidase-based immunodetection, clear signal |
CEP17 probe | FITC; very strong signal, with blurring of large signals | FITC; faint and transient | - | - |
Tissue morphology | Poor definition; control with H&E to view areas of interest | Very poor definition; control with H&E to view areas of interest | Poor definition; control with H&E to view areas of interest | Good definition, allowing simultaneous analysis of amplification and histopathology |
Microscope | Fluorescent | Fluorescent | Fluorescent | Normal light |
Storage | 1 year at -20°C | 1 year at -20°C | 1 year at -20°C | Long period at ambient temperature |
Threshold | OK | OK | CISH threshold must be applied and borderline cases must be evaluated with a dual-probe method (5–10) |