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A. Sejda



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    MO05 - Prognostic and Predictive Biomarkers II (ID 95)

    • Event: WCLC 2013
    • Type: Mini Oral Abstract Session
    • Track: Medical Oncology
    • Presentations: 1
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      MO05.02 - Overexpression of FGFR1 mRNA and protein are more frequent than FGFR1 gene amplification in non-small cell lung cancer (NSCLC) patients (ID 2459)

      16:15 - 17:45  |  Author(s): A. Sejda

      • Abstract
      • Presentation
      • Slides

      Background
      Somatic mutations and gene fusions have been identified as oncogenic drivers in lung cancer, however, a number of lung cancers have no apparent molecular aberration driving oncogenesis. It appears that gene/protein overexpression may sustain these “pan-negative” cancers. Fibroblast growth factors (FGFs) and their receptors (FGFRs) regulate cell proliferation, differentiation, migration and survival and dysregulation of this signaling pathway is observed in a proportion of lung cancers. A number of compounds targeting FGF/FGFR are in clinical development but clinically applicable biomarker assays and companion diagnostics that accurately identify patients with tumors sensitive to these agents are needed. We previously presented cell line data demonstrating that FGFR1 mRNA (ME) or protein expression (PE) better identified FGFR1 inhibitor sensitive tumors compared to gene copy number (GCN). The goal of this study was to examine FGFR1 ME, PE and GCN in a surgically treated NSCLC clinical cohort and explore possible associations with clinical features and prognosis.

      Methods
      Immunohistochemistry, brightfield in situ hybridization, and silver in situ hybridization were used to investigate ME, PE and GCN, respectively, in a cohort of 189 NSCLC surgically-treated patients. PE was scored by the H-score method (0-300) and ME on a semiquantative integer scale (0-4+), both evaluating the entire tumor specimen. GCN was scored on continuous scale by counting the individual signals in 50 cells and determining the average GCN per tumor cell.

      Results
      Amplification (GCN >=4) was present in 8% of the entire cohort and in 11% of the squamous cell carcinoma (SCC) or mixed histology subgroup. No amplifications were found in the adenocarcinomas (ADC) or tumors from never smokers. In contrast, 29% of SCC and ADC patients had high ME (= 4+). Elevated PE (>= 100) was observed in 20% of the cohort, with the highest expression observed in SCC/mixed histology, but 6% of ADCs also showed elevated PE. There was no elevated FGFR1 PE in the never smokers. There was significant correlation but incomplete overlap between biomarkers. There were no prognostic associations, either with overall or disease-free survival, for FGFR1 GCN, ME, or PE. There was excellent inter-observer agreement among the readers of all 3 biomarker assays.

      Conclusion
      Overexpression of FGFR1 mRNA and protein are more frequent than FGFR1 gene amplification in NSCLC patients. Although GCN amplification was restricted to SCC, elevated ME and PE were found in both ADC and SCC. There was no prognostic association with FGFR1 GCN, ME, or PE. These data are consistent with our previous cell line data that showed elevated PE and ME in non-amplified cells and suggests that GCN may not identify all the potential patients who could benefit from FGF/FGFR pathway inhibitors.

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    MO10 - Molecular Pathology II (ID 127)

    • Event: WCLC 2013
    • Type: Mini Oral Abstract Session
    • Track: Pathology
    • Presentations: 1
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      MO10.07 - ALK immunohistochemistry and fluorescence in-situ hybridization in Lung adenocarcinomas from the ETOP Lungscape tumour cohort (ID 2267)

      16:15 - 17:45  |  Author(s): A. Sejda

      • Abstract
      • Presentation
      • Slides

      Background
      The European Thoracic Oncology Platform LungScape database contains 2614 cases of primary resected lung carcinoma from 16 centres with patient demographics, pathological tumour data and detailed clinical follow-up. A total of 1281 cases of adenocarcinoma with >2 years clinical follow-up were selected for analysis of ALK status by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Test positive cases were matched, in order of importance at ratio 1:2, by stage, gender, smoking status, study centre, year of surgery and age with test negative cases -both for IHC and for FISH testing.

      Methods
      Testing was performed in all centres using the same protocol (IHC: Novocastra 5A4 clone antibody at 1:10 dilution, Novolink detection system. FISH: Abbott Vysis ALK break-apart probe). Each centre passed an external QA test using unknown cases in a tissue microarray before conducting the LungScape tumour testing. IHC was scored according to three intensity scores (1+, 2+, 3+) using ‘objective’ methodology previously described [1]. Maximum staining intensity was recorded. Any IHC staining was defined as IHC positive result. FISH preparations were assessed according to the Vysis protocol on all 82 IHCpositive cases plus their 164 IHCnegative matches.

      Results

      IHC cases, n=1281 FISH positive(264 tested)
      IHC negative 1199 (93.6%) 0 (0.0% of 164 controls) FISH specificity: 100%
      IHC 1+ 43 (3.35%) 2 (4.6% of IHC 1+)
      IHC 2+ 16 (1.25%) 6 (37.5% of IHC 2+)
      IHC 3+ 23 (1.8%) 20 (87% of IHC 3+)
      IHC any positive 82 (6.4%) 28 (34.1% of IHC+) FISH sensitivity: 34.1%
      FISH sensitivity was 87% for IHC 3+. IHCpositive/FISHnegative cases (n=54) were mostly IHC 1+ (75.9%), sometimes IHC 2+ (18.5%) and rarely IHC 3+ (5.5%). The frequency of never smokers was higher in the ALK IHCpositive group (29.3%) versus IHCnegative group (18.3%) {p=0.011}. Age, gender and tumour stage did not differ between IHC groups. The hazard of an event for IHCpositive cases decreases by 32% in relapse-free survival {RFS; p=0.03} and by 38% in either time-to-relapse {TTR; p=0.02} or overall survival {OS; p=0.016}. Multivariate models -adjusted for patient and tumour characteristics- indicated that IHC-ALK was a significant predictor for all three time-to-event outcomes (RFS, TTR, OS). In stratified Cox analysis, significantly higher OS was retained in the IHCpositive (HR=0.59, p=0.04) and FISHpositive (HR=0.34, p=0.03) cases in the matched cohorts, while conditional logistic regression yielded non-significant associations with 3-year survival status.

      Conclusion
      In this large cohort of surgically resected primary lung adenocarcinoma: ALK IHC positivity was 6.4%. IHC 3+ staining (prevalence 1.8%) showed 87% probability of ALK FISH positivity ALK IHC positivity was higher in never smokers and related to better clinical outcome ALK testing can be reliably implemented across multiple laboratories {1} Ruschoff et al. Virchows Arch. 2010;457(299-307).

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