Volker Dimmer

Loss of caveolin expression in type I pneumocytes as an indicator of subcellular alterations during lung fibrogenesis

Abstract Caveolin is a major structural protein of caveolae, also known as plasmalemmal vesicles, which are particularly abundant in type I pneumocytes and capillary endothelial cells of lung parenchyma. Here we demonstrate that caveolin expression in the alveolar epithelium of rats and mini pigs is strikingly downregulated after irradiation-induced lung injury. Indirect immunoperoxidase staining with polyclonal anti-caveolin antibodies, confirmed by double fluorescence studies with type I cell-specific monoclonal anti-cytokeratin antibodies or lectins, revealed a dramatic loss of caveolin immunoreactivity in type I pneumocytes. In contrast, caveolin expression increased in endothelial cells. Immunoblotting of lung homogenates from normal and irradiated rats using specific anti-caveolin antibodies confirmed the presence of caveolin in normal tissue and its marked decrease of expression in fibrotic tissue. The loss of caveolin as an important structural protein of caveolae in alveolar epithelial cells may be an early indicator of serious type I cell injury during fibrogenesis. The increase of caveolin immunoreactivity in endothelia of blood vessels may indicate that different types of caveolae and/or different regulatory mechanisms of caveolin expression exist.

DNA histogram interpretation based on statistical approaches.

Image cytometric DNA measurements provide data which are most often interpreted as equivalent to the chromosomal ploidy although the chromosomal and the DNA ploidy are not identical. The common link between them is the cell cycle. Therefore, if destined for DNA ploidy interpretations, the DNA cytometry should be performed on a population‐oriented stochastic basis. Using stochastic sampling the data can be interpreted by applying the rules of stochastic processes. A set of statistical methods is given that enables a DNA histogram to be interpreted objectively and without human interaction. These statistics analyse the precision and accuracy of the entire measurement process. They give in error probabilities for accepting a measurement as reliable, for recognition of stemlines, stemline aneuploidy, and for evaluating so‐called rare events. Nearly 300 image cytometric DNA measurements from breast cancers and rat liver imprints examples have been selected to demonstrate the efficiency of the statistics in each step of interpreting DNA histograms.

Expression of p53 and bcl-2 in correlation to clinicopathological parameters, hormone receptor status and DNA ploidy in breast cancers

The expression of p53 and bcl-2 was immunohistochemically investigated in 61 formalin-fixed, paraffin-embedded invasive breast carcinomas. The study was aimed to elucidate the relationship between both markers and the correlation of p53 and bcl-2, respectively, to clinicopathological variables, to hormone receptor status and to DNA-ploidy. Twenty tumors showed a positive reaction with the monoclonal antibody DO-1 against p53 protein. Its immunohistochemical demonstration was significantly correlated with a tumor size larger than 2 cm, a low estrogen receptor status and DNA-aneuploidy. Bcl-2 was demonstrated in 51 breast cancers. Bcl-2 was preferably seen in low grade and hormone receptor positive tumors. We found a negative correlation between the immunoreactive scores of p53 and bcl-2, but in 17 carcinomas a coexpression of both proteins was seen. Cases with this coexpression did not differ significantly from the other tumors in clinicopathological parameters. In eight of these cases more than 10% of the cells were found to be positive for both markers. In four cases we could show many cells to exhibit both markers as it was assessed by an immunofluorescence double labeling technique.

The Impact of Nucleolar Organizer Regions for the Lymph Node Spread and Prognosis of Invasive Ductal Mammary Carcinoma

In primary tumours of 40 patients with invasive ductal carcinomas the significance of nucleolar organizer regions (NORs) for metastatic spread to the axillary lymph nodes and for the prognosis was assessed. Silver-stained tissue sections were investigated by means of semiautomated image analysis. The nucleolar organizer regions of 100 tumour cell nuclei per specimen were measured. The number as well as the area of the NORs were evaluated together with morphometrical and DNA features, histopathological and clinical data. By means of multivariate discriminant analysis, significant differences between tumours of 20 node-negative and 20 node-positive patients could be found. The mean number of NORs was significantly higher in patients with lymph node metastases (p = 0.0059), whereas the mean area was significantly lower in node-positive patients. By using the NOR number as the only parameter both groups were classified with an overall efficiency of 95%. There was also a significant difference between long-term and short-term survivors by considering the mean number of NORs, but the Auer-type, the 2 cDl value, and the DNA-grade of malignancy were of better predictive value. Within the group of node-negative patients the NOR number was most suitable for distinguishing between good and poor prognosis, whereas within the group of node-positive patients once more the DNA parameters played the most decisive role for predicting prognosis. With regard to the small number of patients the results have to be considered as preliminary. Further investigations in a more extensive population are necessary.

NUCLEAR IMAGE ANALYSIS OF IMMUNOHISTOCHEMICALLY STAINED CELLS IN BREAST CARCINOMAS

Hitherto, the relationship between malignancy-associated morphological features in single tumour cells and the expression of markers indicating functional properties of these cells remained widely unknown. This study was aimed at describing differences in the size, shape and chromatin structure between tumour cells with different marker expression for progesterone receptors (PgR) and p53. Two series of breast cancers, consisting of 50 PgR-positive, and 39 p53-negative and 49 p53-positive mammary carcinomas, were investigated. The immunohistochemical staining was performed on paraffin sections using 3-amino-9-ethylcarbazole as the chromogenic substrate. By means of a cytometry workstation equipped with a computer-controlled motorised scanning stage, about 500 positive and negative tumour cells in each case were localised in the microscope and categorised by a scoring system for their staining intensity. After destaining, the tissue sections were Feulgen-stained. Then, all the tumour cells were relocated automatically and analysed by high resolution image cytometry. Among the numerous size, shape, and texture features used in the system, several variables of the nuclear contour and chromatin structure were found to be significantly different between the positive and negative tumour cell populations. Nuclei without PgR had more malignancy-associated morphological features than PgR-positive cells. Whereas p53-negative nuclei had a higher degree of regularity, their positive counterparts exhibited higher DNA ploidy values.

Grading and Prognosis of Invasive Ductal Mammary Carcinoma by Nuclear Image Analysis in Tissue Sections

In primary tumours of 84 patients with invasive ductal carcinomas the prognostic significance of the nuclear image was assessed. Feulgen stained tissue sections were investigated by image cytometry. At least 150 tumour cell nuclei as well as 50 lymphocytes or trout erythrocytes for diploid reference were measured in each specimen. 35 morphological features, including those of the chromatin pattern, were derived from the digitized nuclear images. By means of multivariate discriminant analysis, significant differences could be found between tumours of 41 node-negative and 43 node-positive patients. The differences were sufficiently large to distinguish subgroups with low and high risk of lymph node involvement. Irrespective of lymph node status, 66 patients with an adequate 5 year follow-up were divided into two groups according to their survival time. The classification results revealed a clear relationship between characteristics of the nuclear image and prognosis. By image cytometry it is thus possible to separate both node-positive and node-negative patients into subgroups with increasing risk of recurrence. The results indicate that nuclear image analysis provides prognostic information in addition to established prognostic factors, such as histological grade and tumour stage.

Correlation between p53 status, DNA ploidy, proliferation rate and nuclear morphology in breast cancer. An image cytometric study

The study was designed to detect differences in the nuclear morphology of tumours and tumour cell populations with different p53 expression in correlation with DNA ploidy and proliferation rate. The paraffin sections from routinely processed samples of 88 breast cancers were immunostained with the monoclonal p53‐antibody DO‐1. After localization and evaluation with a scoring system the sections were destained and stained by the Feulgen method. The nuclei were relocated automatically and measured by means of the image cytometry workstation. Significant differences between the tumours and tumour cell populations with different p53 expression were found in the euploid tumours as well as in the aneuploid tumours and in the breast cancers with a high proliferation rate. The breast cancers with a low immunoreactive score (IRS 1–4) differ from the negative cancers as well as from the cancers with a higher immunoreactive score (IRS 5–12). Evaluating the nuclear populations of the p53 positive cancers, there were differences in the features of the chromatin amount and distribution in the groups of the euploid breast cancers and in cancer with a high proliferation rate. In contrast, the nuclear populations of the aneuploid cancers did not show any differences in their nuclear morphology. The results showed the different impacts of the p53 expression, DNA ploidy and the proliferation rate on the nuclear morphology in breast cancer.

DNA Ploidy and Chromosomal Imbalances in Invasive Ductal Breast Cancer. A Comparative Study of DNA Image Cytometry and Comparative Genomic Hybridization (CGH)

Chromosomal imbalances were analyzed in 62 breast cancers with different DNA ploidy by CGH. The results of DNA image cytometry and CGH are consistent with peridiploid and aneuploid cases. The peritetraploid tumors harbored a high number of chromosomal imbalances, as a hint for an unfavorable prognosis. The quantitative analysis of imbalances highlighted the role of different physical constituents of the chromosome, and of chromosomal losses in different DNA ploidy groups. The peritetraploid and aneuploid tumors differed from the peridiploid tumors in losses at 8p and 18q. The peritetraploid cancers exhibited more gains at 8q, the aneuploid tumors more losses at 17p than their peridiploid counterparts. The aneuploid cases differed from the peritetraploid tumors in a higher number of losses at 11q and 14q. Combinations of imbalances provide further insights into the genetic background of DNA ploidy. Hypotheses for the progression from peridiploid to nondiploid breast cancers are given. Figures on http://www.esacp.org/acp/2000/20-2_3/friedrich.htm.

Metastasizing APUD Cell Tumours of the Human Gastrointestinal Tract: Light Microscopic and Karyometric Studies

A total of 11 metastasizing gastrointestinal APUD cell tumours from biopsy and autopsy files were reclassified according to Soga and Tazawa as well as to WHO Histologic Classification of Tumours. The much higher proportion of APUD cell tumours in autopsies (11 cases from 1000 autopsies in comparison with 22 cases from 22 000 biopsies) demonstrate that the majority of them will not be discovered during the patients life. EC cell carcinoids (type A) predominate in both non-metastasizing and metastasizing gastrointestinal APUD cell tumours. Metastases from EC cell carcinoids occurred only in regional lymph nodes and in the liver. The APUD cell tumours originating in the pancreas represent the most frequently metastasizing gastrointestinal carcinoids. Besides in the liver and in regional lymph nodes metastases from pancreatic APUD cell tumours were seen in the skin, the brain and the skeleton. One case with two (pancreatic, bronchial) competitive primary APUD cell tumours and a skin metastasis was studied by means of automated cell image analysis. Cell populations of these three tumour sites were characterized by morphometric and densitometric nuclear parameters. It could be demonstrated that the skin metastasis consisted of a cell population, which occurred as a subpopulation in the primary tumour of the bronchus. The results of karyometric investigations supported the hypothesis that single components of tumours can metastasis selectively.

Morphological heterogeneity of p53 positive and p53 negative nuclei in breast cancers stratified by clinicopathological variables.

The study was aimed to detect differences in nuclear morphology between nuclear populations as well as between tumours with different p53 expression in breast cancers with different clinicopathological features, which also reflect the stage of tumour progression. The p53 immunohistochemistry was performed on paraffin sections from 88 tumour samples. After the cells had been localised by means of an image cytometry workstation and their immunostaining had been categorised visually, the sections were destained and stained by the Feulgen protocol. The nuclei were relocated and measured cytometrically by the workstation. There were significant differences in the nuclear features between tumours as well as between nuclear populations with different p53 expression in the most subgroups. The variability of nuclear shape in tumour groups, classified by the tumour size or the lymph node status, increase with the p53 immunoreactive score, whereas in tumours grouped by the Bloom–Richardson grade features of the chromatin distribution were different between the p53 staining categories. The nuclear subpopulations showed differences in the amount and distribution of chromatin in most subgroups. The results demonstrate the relationship between the nuclear morphology and the p53 expression in different stages of breast cancers. The p53 status is an important factor of the biological behaviour but not the only one.