[Molecular diagnostics of epidermal growth factor receptor in non-small cell lung cancer]

One of the most useful markers of non-small cell lung cancer is epidermal growth factor receptor (EGFR) protein expression. Recently it was found that the EGFR gene may be amplified or mutated in non-small cell lung cancer rendering this gene product an ideal target for therapy. The introduction of molecularly targeted therapy into the clinical practice represents a milestone in the management of non-small cell lung cancer. However, our knowledge on the prognostic and predictive factors that will define the efficiency of anti-EGFR therapy is limited. In clinical practice, some common patient and disease features (e. g., smoking habit, gender, histological type) are still more dependable predictors than the fine molecular properties that may directly affect therapeutic response. The indication of anti-EGFR therapy in Hungary is based on the immunohistochemical detection of the EGFR protein, therefore, it is important that these tests are performed as reliably as possible. On the other hand, mutations in the EGFR gene may render the tumour resistant or, in contrary, especially sensitive to EGFR inhibitor therapy. The sequence of the diagnostic steps to define the genotype and phenotype of non-small cell lung cancer has a great importance in terms of cost-efficiency of the therapy.