• Home
  • Search Results
  • Correlation of EGFR expression, gene copy number and clinicopathological status in NSCLC.

Correlation of EGFR expression, gene copy number and clinicopathological status in NSCLC.

Diagnostic pathology (2014-09-18)
Rania Gaber, Iris Watermann, Christian Kugler, Nils Reinmuth, Rudolf M Huber, Philipp A Schnabel, Ekkehard Vollmer, Martin Reck, Torsten Goldmann
ABSTRACT

Epidermal Growth Factor Receptor (EGFR) targeting therapies are currently of great relevance for the treatment of lung cancer. For this reason, in addition to mutational analysis immunohistochemistry (IHC) of EGFR in lung cancer has been discussed for the decision making of according therapeutic strategies. The aim of this study was to obtain standardization of EGFR-expression methods for the selection of patients who might benefit of EGFR targeting therapies. As a starting point of a broad investigation, aimed at elucidating the expression of EGFR on different biological levels, four EGFR specific antibodies were analyzed concerning potential differences in expression levels by Immunohistochemistry (IHC) and correlated with fluorescence in situ hybridization (FISH) analysis and clinicopathological data. 206 tumor tissues were analyzed in a tissue microarray format employing immunohistochemistry with four different antibodies including Dako PharmDx kit (clone 2-18C9), clone 31G7, clone 2.1E1 and clone SP84 using three different scoring methods. Protein expression was compared to FISH utilizing two different probes. EGFR protein expression determined by IHC with Dako PharmDx kit, clone 31G7 and clone 2.1E1 (p ≤ 0.05) correlated significantly with both FISH probes independently of the three scoring methods; best correlation is shown for 31G7 using the scoring method that defined EGFR positivity when ≥ 10% of the tumor cells show membranous staining of moderate and severe intensity (p=0.001). Overall, our data show differences in EGFR expression determined by IHC, due to the applied antibody. Highest concordance with FISH is shown for antibody clone 31G7, evaluated with score B (p=0.001). On this account, this antibody clone might by utilized for standard evaluation of EGFR expression by IHC. The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_165.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Hydrogen peroxide solution, purum p.a., ≥35% (RT)
Sigma-Aldrich
Hydrogen peroxide solution, contains ~200 ppm acetanilide as stabilizer, 3 wt. % in H2O
Sigma-Aldrich
Hydrogen peroxide solution, 50 wt. % in H2O, stabilized
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 35 wt. % in H2O
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 30 wt. % in H2O, meets USP testing specifications
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 30 wt. % in H2O, ACS reagent
Sigma-Aldrich
Hydrogen Peroxide Solution, 30% (w/w), puriss. p.a., reag. ISO, reag. Ph. Eur.
Sigma-Aldrich
Hydrogen peroxide solution, tested according to Ph. Eur.
Millipore
Hydrogen peroxide solution, 3%, suitable for microbiology
Supelco
Hydrogen peroxide solution, ≥30%, for trace analysis
Sigma-Aldrich
Hydrogen peroxide solution, 34.5-36.5%
Sigma-Aldrich
Hydrogen peroxide solution, 30 % (w/w) in H2O, contains stabilizer
Supelco
Hydrogen peroxide solution, 30 % (w/w), for ultratrace analysis
Sigma-Aldrich
Hydrogen peroxide solution, contains potassium stannate as inhibitor, 30-32 wt. % in water, semiconductor grade, 99.999% trace metals basis