engleski

EGFR protein and gene level in clear cell renal cell carcinoma

The role of epidermal growth factor receptor (EGFR) in the pathogenesis of clear cell renal cell carcinoma (CCRCC) is still not well recognized. The aim of study was to analyze the expression of EGFR on tumor cells in CCRCC, to correlate its value with EGFR gene copy number and to compare analyzed parameters with clinicopathological characteristics of CCRCC including the patients’ survival. Tissue microarrays (TMA) from the cohort of 94 archive formalin fixed and paraffin embedded CCRCC were immunohistochemically stained for EGFR expression and evaluated as a percentage and intensity of membranous staining (histoscore, HS). EGFR gene copy number changes was investigated by means of fluorescence in situ hybridization (FISH). Clinicopathologic data included tumor size, stage and nuclear grade (NG). Membranous EGFR expression was detected in 84/91 cases (92.3%), with moderate to strong staining (HS 2 and 3) in 52 cases (57.14%), and only week cytoplasmic EGFR in 29 cases (31.86%). Overexpression of EGFR was related to worse prognostic parameters, bigger tumors (p=0.018), higher NG (p=0.0002), pT stage (p=0.036) and lower overall survival (p=0.046). FISH method revealed polysomy 7 associated with protein EGFR overexpression in CCRCC tumor cells (p<0.001) but not with clinicopathological parameters. No amplification was found. Survey of CCRCC with TMA technique highlights more aggressive subtype of CCRCC with overexpression EGFR in tumors cells that might have some clinical implication. FISH analysis showed that EGFR gene dosage can influence on protein expression through polysomy rather than amplification.

EGFR; FISH; immunohistochemistry; renal cell carcinoma;

DOI 10.1007/s00428-009-0805-z