Altered DNA repair capacity and bleomycin sensitivity as risk markers for non-small cell lung cancer.

DNA repair capacity in human peripheral blood lymphocytes was monitored by the repair rate of bleomycin-induced DNA damage using an alkaline single-cell gel electrophoresis assay (comet assay). DNA repair capacity, after 15 min repair time, in lymphocytes of non-small cell lung cancer patients (n = 160) and controls (n = 180) was 67% and 79.3%, respectively (p < 0.0004). Bleomycin sensitivity defined as the tail moment of bleomycin-treated peripheral blood lymphocytes, without allowing time for DNA repair, was significantly higher in lung cancer patients than in tumor-free hospital controls (p < 0.0001). There was no correlation, in either patient or control group, between the bleomycin sensitivity and DNA repair capacity with age or gender. The median values of DNA repair capacity and sensitivity in controls were used as the cut-off points for calculating odds ratios (OR). After adjustment for age, gender and smoking status, the cases vs. controls had reduced DNA repair capacity (OR = 2.1; 95% confidence limit [CL] 1.1-4.0) and increased bleomycin sensitivity (OR = 4; 95% CL 2.2-7.4). For current smokers, the adjusted risk associated with bleomycin sensitivity was 2.3 (95% CL 1.1-4.9). We conclude that our standard comet assay as a phenotypical repair test has sufficient sensitivity and rapidity allowing application to both native and cryopreserved lymphocytes. Bleomycin sensitivity and DNA repair capacity were found to be 2 independent susceptibility markers for non-small cell lung cancer, confirming similar investigations with different marker end points. The latter were much more time consuming than the method used in our study. Thus, the comet assay is more suitable for screening large numbers of individuals in epidemiological studies. Validation of this assay in large prospective studies for the identification of subjects at high risk for non-small cell lung cancer is now warranted.

Rapid screening assay for mutagen sensitivity and DNA repair capacity in human peripheral blood lymphocytes.

Individual susceptibility to carcinogens, an important determinant of disease risk, is influenced by host factors such as the ability to repair DNA lesions. In order to identify subjects who are at high risk, we have developed a microgel electrophoresis assay for use in molecular epidemiological studies. The assay was validated in a pilot case-control study: Peripheral blood lymphocytes were collected from 100 patients with lung cancer and 110 control patients without cancer and from the same hospital, and stored at -80 degrees C. After thawing, phytohaemagglutinin-stimulated cells were treated with bleomycin at 20 microg/ml for 30 min and the extent of DNA damage and DNA repair capacity were determined by microgel electrophoresis. Peripheral blood lymphocytes from patients with lung cancer were significantly more sensitive to mutagens than those from controls and showed reduced DNA repair capacity (both P < 0.001). Both endpoints were independent risk factors for smoking-related lung cancer. Repeated analysis of peripheral blood lymphocytes from the same individual demonstrated good reproducibility of the assay. Cryopreservation of the lymphocytes for less than or = 12 months did not significantly affect their sensitivity. Our standardized microgel electrophoresis assay is suitable for determining individual sensitivity to mutagens and DNA repair capacity: it is sensitive and faster than cytogenetic assays, and can be applied to native and cryopreserved peripheral blood lymphocytes.

[Lung perfusion-ventilation scintigraphy in squamous cell carcinoma of the lung]. / Lungenperfusions- und Ventilationsszintigraphie beim Plattenepithelkarzinom der Lunge.

The effect of tumour size, as determined surgically, and tumour position, as determined by bronchoscopy, on ventilation and perfusion scintigraphy was examined in 53 patients with squamous cell carcinomas of the lung. The findings were compared with reduction in one-second-capacity. Central tumours were frequently associated with marked reduction in perfusion. In these patients there was a linear positive correlation between ventilation and one-second-capacity. The reduction in perfusion, and the need to measure this, became with more peripheral tumours. There was a correlation between ventilation and tumour size in patients with V/Q quotient of greater than 1.2. The results show that tumour size and position do not necessarily indicate operability. For planning surgery of central tumours, perfusion scintigraphy therefore occupies an important position.

Survival of operated bronchus carcinoma patients: a prospective study.

Maximum diameter, tumour volume, and inflammatory response of host tissue in 282 surgical specimens with primary carcinoma of the bronchus were measured. Cell type, pT- and pN-stage, maximum diameter and volume of the primaries, and inflammatory response of host tissue were analyzed in respect to survival of the patients. Date of death was evaluated by quarterly communications with the house physicians. Survival rates were computed by use of Kaplan-Meier estimation. Mean survival of all patients was calculated at 480 days. Lymph node involvement and tumour volume were found to have a major influence on survival. In accordance with the weak contribution of maximum diameter of the tumour to survival, no major differences in survival between pT1- and pT2-stage were found. If severe inflammatory response at the tumour boundary was noted, patients showed slightly increased survival in all tumour stages. Cell type and tumour grading were found to be of minor influence in respect to survival.

The intermediate filament cytoskeleton of malignant mesotheliomas and its diagnostic significance.

The intermediate filament cytoskeleton of epithelial, biphasic, and fibrous malignant pleural mesotheliomas was studied by immunohistochemistry and gel electrophoresis. The results were compared with data similarly obtained from lung adenocarcinomas. All mesotheliomas immunostained with various monoclonal and polyclonal antibodies against cytokeratins. By double immunofluorescence microscopy, coexpression of cytokeratins and vimentin was found in the fusiform cells of biphasic and fibrous mesotheliomas. As determined by two-dimensional gel electrophoresis, lung adenocarcinomas exclusively expressed Cytokeratins 7, 8, 18, and 19, and the same polypeptides were found in the fibrous mesotheliomas. These four cytokeratins were also found in the epithelial and biphasic mesotheliomas, most of which, however, also expressed, additional cytokeratins, such as the basic Polypeptide 5 and, in some cases, Cytokeratins 4, 6, 14, and 17. The results demonstrate the epithelial nature of all types of malignant mesotheliomas and thus justify their classification as carcinomas. When epithelial morphology is evident, the pattern of cytokeratin expression is usually more complex, as indicated by the synthesis, in addition to the "simple epithelial" pattern (7, 8, 18, and 19), of certain cytokeratin polypeptides which hitherto have been presumed to be typical of stratified epithelia. This cytokeratin complexity and the coexpression of vimentin and cytokeratins in certain forms of mesotheliomas indicate that these tumors are a clearly distinct and complex group of carcinomas. Their special cytoskeletal filament protein expression should prove useful in differentiating mesotheliomas from other carcinomas, particularly from adenocarcinomas growing in the lung.