Clinical and prognostic importance of expression of epidermal growth factor receptors in non-small-cell lung carcinoma

Abstract

Radioligand assay demonstrated that in patients with non-small-cell lung cancer, expression of epidermal growth factor receptors in the tumor is higher than in non-tumor tissue. Expression of epidermal growth factor receptors in tumor and non-tumor lung tissue does not correlate with the stage and metastasizing of the disease and tumor histology. It is also shown that expression of epidermal growth factor receptors in tumor and non-tumor tissue is associated with lower survival rate.Key Words: epidermal growth factor receptors; non-small-cell lung cancer; total and recurrence-free survival Lung cancer affects about one million people per year and is the most common cause of death among cancer patients in the majority of countries. It is now accepted that the outcome of treatment can be predicted by a number of clinical and morphological factors [2]. Biochemical parameters reflecting biological activity of tumor cells and tumor process in the whole are also very important.Previous studies of the mechanisms regulating tumor cell growth in the tracheobronchial tree demonstrated that lung cancer cells produce polypeptide growth regulators acting via a auto/paracrine mechanism [6][7][8]12,[15][16][17][18]. Among these polypeptides, epidermal (EGF) and transforming (a-TGF) growth factors are highly active and most studied regulators. These factors belong to the EGF-like peptide family and interact with common receptors on the membrane of target cells. It was shown that EGF control the growth of not only normal cells, but also their transformed malignant variants. This factor is a potent in vivo and in vitro mitogen tor epitheliocytes and connective tissue cells [3,4].Receptor of EGF (EGFR) is now considered as a prognostic tissue marker for tumors of various histogenesis [1,10]. However, despite extensive experimental and clinical investigation, the role of EGF-like peptides and their receptors in different tumors, in particular non-small-cell lung cancer (NSCLC) remained poorly understood. The aim of the present study was to evaluate the expression of EGFR in tumor and normal lung tissue and determine the importance of these parameters tor NSCLC prognosis. Sixty-three patients aged 22-78 years with NSCLC observed and treated at the MATERIALS AND METHODS Laboratory of Clinical

Molecular Markers of Tumors

“…A series of our radioligand studies with 125 I-labeled EGF with subsequent separation on hydroxylapatite (the «golden standard» for EGFR detection in the membrane fraction of tissues) showed the presence of these receptors in 32-75% of malignant tumors ( Table 2). They were most often detected in non-small-cell lung cancer (NSLC), which was also characterized by a signifi cant decrease in relapse-free and overall survival at EGFR level >20 fmol/mg protein [16]. These data acquired new practical signifi cance recently, when drugs specifi cally blocking activity of EGFR were allowed for clinical trials and practical use: monoclonal antibodies to the receptor (Erbitux) and inhibitors of its internal tyrosine kinase (Iressa, Tarceva), realizing the fi rst stage of the mitogenic signal transmission [8,36].…”