Pathology, classification, and staging of lung tumors

The histopathogical, immunohistochemical, and genetic characterization of specimens of, mostly advanced, lung tumors that show variable phenotypes in biopsies of just 1-2 mm does not allow conclusions regarding causal factors (e.g., smoking, radon, asbestos etc.) or further progress of the disease. Therapeutical approach and the still unfavorable prognosis remain essentially, as in the last thirty years,to be characterized by TNM and performance status of the individual patient and,to a lesser extent, by the main histological type of tumor. In recent years, our knowledge of the quite variable biology of tumors has been significantly increased by the use of immunohistochemical methods and molecular biology. These methods facilitated an improved qualitative and quantitative characterization of heterogeneously differentiated lung tumors (e.g., neuroendocrine/blastomatoid portions etc.). The detection of genetic alterations of tumor suppressor genes and oncogenes is, at the moment, only of scientific interest. The heterogeneity of tumors is emphasized by results obtained by molecular genetic techniques. A connection between the detected genetic anomalies and histomorphological growth patterns can not be seen. At the present time, the validity of individual findings for a correlation between operability, tumor progress, chemotherapy and prognosis is not sufficiently elucidated by investigations nor secured.