HER-2 testing in breast cancer using parallel tissue-based methods
View abstract on PubMed
Summary
This summary is machine-generated.Immunohistochemistry (IHC) is an efficient primary test for HER-2 oncogene in breast cancer. Fluorescence in situ hybridization (FISH) testing is recommended only for indeterminate (2+) IHC results, ensuring cost-effectiveness and accuracy.
Area Of Science
- Oncology
- Molecular Diagnostics
- Breast Cancer Research
Background
- The HER-2 oncogene is a crucial prognostic and predictive factor in breast cancer.
- Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) are methods for HER-2 testing, with ongoing debate on their comparative accuracy for predicting trastuzumab response.
- Critical evaluation of FISH for screening purposes is needed.
Purpose Of The Study
- To assess the correlation between FISH and IHC results for HER-2/neu gene status.
- To determine HER-2 gene status in tumors with indeterminate (2+) IHC results.
- To confirm gene amplification in tumors with positive (3+) and negative (0 or 1+) IHC results.
Main Methods
- A quality control and assurance program evaluated HER-2 testing by FISH on 2963 breast cancer specimens from 135 institutions.
- FISH testing was performed in parallel with IHC on all specimens.
- IHC sensitivity, specificity, and predictive values were calculated using FISH as the standard.
Main Results
- IHC demonstrated high accuracy: positive predictive value of 91.6% for 3+ scores and negative predictive value of 97.2% for 0 or 1+ scores.
- IHC sensitivity (92.6%) and specificity (98.8%) were robust.
- FISH exhibited a higher failure rate (5% vs 0.08%), significantly higher reagent costs ($140 vs $10), and longer testing and interpretation times compared to IHC.
Conclusions
- An efficient HER-2 testing algorithm utilizes IHC as the primary method.
- FISH testing should be reserved for cases with indeterminate (2+) IHC results.
- Robust quality control and assurance programs are essential for reliable HER-2 testing strategies.