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Updated: Aug 6, 2026
Heterogeneity Mapping of Protein Expression in Tumors using Quantitative Immunofluorescence
Published on: October 25, 2011
AQUA and FISH analysis of HER-2/neu expression and amplification in a small cell lung carcinoma tissue microarray
J M Giltnane1, J R Murren, D L Rimm
1Section of Medical Oncology, Yale University School of Medicine, New Haven, CT 06510, USA.
Aims:
Most small cell lung carcinoma (SCLC) patients have metastatic disease at the time of diagnosis and are faced with poor prognosis and limited treatment options. Reports of HER-2/neu gene amplification and overexpression in this malignancy have raised the possibility of applying targeted immunotherapy with trastuzumab, the monoclonal antibody used to treat metastatic breast cancer. However, a review of the studies measuring HER-2/neu gene amplification and protein expression in SCLC reveals discordant results. The aim of the present study was to re-examine HER-2/neu expression in SCLC in relation to gene copy number using the new, highly sensitive, immunofluorescence automated quantitative analysis (AQUA) technology.
Methods And Results:
Fluorescence in situ hybridization (FISH) was used to measure HER-2/neu gene copy number and amplification status and AQUA was used to measure protein expression in a series of 23 SCLC tumours on a tissue microarray. None of the 17 SCLC specimens assessable by FISH exhibited HER-2/neu gene amplification as defined by a HER-2/neu/chromosome 17 ratio = or > 2. Twelve of 17 (70.1%) SCLC samples were polysomic for chromosome 17 with corresponding increases in HER-2/neu gene copy numbers. Intermediate levels of protein expression corresponding to AQUA scores in the range of 4-24 were detected in all 23 specimens. High protein expression levels corresponding to AQUA scores up to 83, observed previously in association with gene amplification and poor prognosis in breast cancer cases, were not detected in the present study. No statistically significant association was observed between absolute chromosome 17 or HER-2/neu gene copy numbers and protein expression levels in tumour cells (P > 0.45).
Conclusions:
The lack of gene amplification and robust HER-2/neu protein expression in SCLC tumour cells in this series does not suggest a prominent role for the HER-2/neu gene in SCLC tumour progression and does not support the general applicability of targeted immunotherapy with trastuzumab to this malignancy.
Insights
HER-2/neu gene amplification and robust protein expression were not detected in small cell lung carcinoma (SCLC) tumors. This finding does not support the use of trastuzumab targeted immunotherapy for SCLC treatment.
Area of Science:
- Oncology
- Molecular Biology
- Immunotherapy
Background:
- Small cell lung carcinoma (SCLC) often presents with metastatic disease and has a poor prognosis.
- HER-2/neu gene amplification and overexpression have been reported in SCLC, suggesting potential for targeted therapy with trastuzumab.
- Previous studies on HER-2/neu expression in SCLC have yielded conflicting results.
Purpose of the Study:
- To re-examine HER-2/neu expression in SCLC.
- To correlate HER-2/neu gene copy number with protein expression.
- To evaluate the potential for trastuzumab immunotherapy in SCLC.
Main Methods:
- Utilized fluorescence in situ hybridization (FISH) to assess HER-2/neu gene copy number and amplification.
- Employed automated quantitative analysis (AQUA) technology for precise measurement of HER-2/neu protein expression.
- Analyzed 23 SCLC tumor samples on a tissue microarray.
Main Results:
- No HER-2/neu gene amplification was found in 17 assessable SCLC specimens (HER-2/neu/chromosome 17 ratio < 2).
- 70.1% of SCLC samples showed polysomy for chromosome 17, with increased HER-2/neu gene copy numbers.
- All samples exhibited intermediate protein expression; high expression levels, as seen in breast cancer, were absent. No significant association between gene copy number and protein levels was observed.
Conclusions:
- The absence of HER-2/neu gene amplification and robust protein expression in SCLC suggests limited involvement of this gene in tumor progression.
- These findings do not support the broad application of trastuzumab-based targeted immunotherapy for SCLC.
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