[New aspects of lung tumor pathology]

The "new" 3rd WHO classification of lung tumors 1999 is described in nine groups of malignant broncho-pulmonary neoplasias. 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 long tumors (e.g., neuroendokrine/blastomatoid portions etc.). The detection of genetic alterations of tumor suppressors (Rb/p53/FIHT/TGF beta R-2 etc.) and oncogenes (e.g., myc/fos/blc-2/ras/erbB etc.) is, at the moment, only of scientific interest. The genetic heterogeneity of tumors is emphasized by results obtained with the comparative genomic hybridization (CGH). In small-cell carcinomas of the lung more than seven variable chromosomal alterations--especially loss of genetic material in the regions 3p, 10q, and 4q--can be detected in a tumor. Adenocarcinomas show losses of genetic material on chromosomes 9 and 19, and/or gains on chromosome 1. Squamous cell carcinomas frequently exhibit losses on chromosome 2 and gains on chromosome 3. 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. The histopathological, 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 unfavourable 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.