A Feature Set for Cytometry on Digitized Microscopic Images

Feature extraction is a crucial step in most cytometry studies. In this paper a systematic approach to feature extraction is presented. The feature sets that have been developed and used for quantitative cytology at the Laboratory for Biomedical Image Analysis of the GSF as well as at the Center for Image Analysis in Uppsala over the last 25 years are described and illustrated. The feature sets described are divided into morphometric, densitometric, textural and structural features. The latter group is used to describe the eu‐ and hetero‐chromatin in a way complementing the textural methods. The main goal of the paper is to bring attention to the need of a common and well defined description of features used in cyto‐ and histometrical studies. The application of the sets of features is shown in an overview of projects from different fields. Finally some rules of thumb for the design of studies in this field are proposed. Colour figures can be viewed onhttp://www.esacp.org/acp/2003/25‐1/rodenacker.htm.

DNA Amplifications and Aneuploidy, High Proliferative Activity and Impaired Cell Cycle Control Characterize Breast Carcinomas with Poor Prognosis

In order to explore whether specific cytogenetic abnormalities can be used to stratify tumors with a distinctly different clinical course, we performed comparative genomic hybridization (CGH) of tumors from patients who were diagnosed with metastatic disease after an interval of less than 2 years or who remained free from distant metastases for more than 10 years. All patients presented with distant metastases after mastectomy indicating that none of the patients in this study was cured and free of remaining tumor cells. Tumors in the group of short‐term survivors showed a higher average number of chromosomal copy alterations compared to the long‐term survivors. Of note, the number of sub‐chromosomal high‐level copy number increases (amplifications) was significantly increased in the group of short‐term survivors. In both short‐ and long‐term survivors recurrent chromosomal gains were mapped to chromosomes 1q, 4q, 8q, and 5p. Copy number changes that were more frequent in the group of short‐term survivors included gains of chromosome 3q, 9p, 11p and 11q and loss of 17p. Our results indicate that low‐ and high grade malignant breast adenocarcinomas are characterized by a specific pattern of chromosomal copy number changes. Furthermore, immunohistochemical evaluation of the expression levels of Ki‐67, p27KIP1, p21WAF1, p53, cyclin A and cyclin E revealed a correlation between increased proliferative activity and poor outcome.

Application of Multilevel Models to Morphometric Data. Part 2. Correlations

Multilevel organization of morphometric data (cells are “nested” within patients) requires special methods for studying correlations between karyometric features. The most distinct feature of these methods is that separate correlation (covariance) matrices are produced for every level in the hierarchy. In karyometric research, the cell‐level (i.e., within‐tumor) correlations seem to be of major interest. Beside their biological importance, these correlation coefficients (CC) are compulsory when dimensionality reduction is required. Using MLwiN, a dedicated program for multilevel modeling, we show how to use multivariate multilevel models (MMM) to obtain and interpret CC in each of the levels. A comparison with two usual, “single‐level” statistics shows that MMM represent the only way to obtain correct cell‐level correlation coefficients. The summary statistics method (take average values across each patient) produces patient‐level CC only, and the “pooling” method (merge all cells together and ignore patients as units of analysis) yields incorrect CC at all. We conclude that multilevel modeling is an indispensable tool for studying correlations between morphometric variables.

In VitroModel for Studying Malignancy Associated Changes

Malignancy associated changes (MAC) can be defined as subtle morphological and physiologic changes that are found in ostensibly normal cells of patients harboring malignant disease. It has been postulated that MAC have a potential to become a useful tool in detection, diagnosis and prognosis of malignant diseases. An in vitro cell culture model system was designed to study interactions between non‐small cell lung cancer (NSCLC) and the normal bronchial epithelium of the human respiratory tractin vivoto see if the MAC‐like phenomenon can be detected in such a system. In this study we examined changes in nuclear features of normal human bronchial epithelial cells (NHBE) when they were co‐cultured with cells derived from a lung cancer cell line NCI‐H460. Using discriminant function analysis, nuclear features were determined which allow maximal discrimination between normal cells incubated with or without cancerous cells. Our results demonstrate that MAC appear to be specific to changes induced by malignancy, and that these changes differ from those induced by growth factors in the serum. This study provides evidence in support to the hypothesis that MAC are induced by a soluble factor(s) released by malignant cells. Colour figure can be viewed onhttp://www.esacp.org/acp/2003/25‐2/sun.htm.

Earliest Detection of Oral Cancer Using Non-Invasive Brush Biopsy Including DNA-Image-Cytometry: Report on Four Cases

Objective: We describe four patients presenting early oral cancers, detected cytologically on non‐invasive brush biopsies including DNA‐image cytometry as an adjunctive method before histology on scalpel biopsies confirmed the evidence of malignancy.Methods: Brush biopsies were performed and smears thereof investigated cytologically. After Feulgen restaining, DNA‐measurements were performed using a DNA‐Image‐Cytometer.Case reports: Oral squamous cell carcinomas were diagnosed cytologically in macroscopically suspicious lesions and malignancy confirmed by DNA‐cytometry. The initially performed scalpel biopsies did neither supply evidence of oral cancer nor of severe dysplasia. After at least one to 15 months the occurrence of cancer was finally proven histologically on a second scalpel biopsy each (three microinvasive and onein situcarcinoma).Conclusion: Non‐invasive brush biopsies are a suitable instrument for early cytologic detection of cancer of the mouth. DNA‐image‐cytometry, as an adjunctive method, can be used to confirm the cytologic diagnosis or suspicion of cancer in patients with doubtful lesions (dysplasias). DNA‐aneuploidy is a marker for (prospective) malignancy in smears of the oral cavity, which may detect malignancy months prior to histology. In future this method could be used as a mass screening tool in dentists practise. Colour figures can be viewed onhttp://www.esacp.org/acp/2003/25‐4/remmerbach.htm.

Application of Multilevel Models to Morphometric Data. Part 1. Linear Models and Hypothesis Testing

Morphometric data usually have a hierarchical structure (i.e., cells are nested within patients), which should be taken into consideration in the analysis. In the recent years, special methods of handling hierarchical data, called multilevel models (MM), as well as corresponding software have received considerable development. However, there has been no application of these methods to morphometric data yet. In this paper we report our first experience of analyzing karyometric data by means of MLwiN – a dedicated program for multilevel modeling. Our data were obtained from 34 follicular adenomas and 44 follicular carcinomas of the thyroid. We show examples of fitting and interpreting MM of different complexity, and draw a number of interesting conclusions about the differences in nuclear morphology between follicular thyroid adenomas and carcinomas. We also demonstrate substantial advantages of multilevel models over conventional, single‐level statistics, which have been adopted previously to analyze karyometric data. In addition, some theoretical issues related to MM as well as major statistical software for MM are briefly reviewed.

Risk Biomarker Assessment for Breast Cancer Progression: Replication Precision of Nuclear Morphometry

Nuclear morphometry is a method for quantitative measurement of histopathologic changes in the appearance of stained cell nuclei. Numerous studies have indicated that these assessments may provide clinically relevant information related to the degree of progression and malignant potential of breast neoplasia. Nuclear features are derived from computerized analysis of digitized microscope images, and a quantitative Feulgen stain for DNA was used. Features analyzed included: (1) DNA content; (2) nuclear size and shape; and (3) texture features, describing spatial features of chromatin distribution. In this study replicated measurements are described on a series of 54 breast carcinoma specimens of differing pathologic grades. Duplicate measurements were performed using two serial sections, which were processed and analyzed separately. The value of a single feature measurement, the nuclear area profile, was shown to be the strongest indicator of progression. A quantitative nuclear grade was derived and shown to be strongly correlated with not only the pathologic nuclear grade, but also with tubule formation, mitotic grade, and with the overall histopathologic grade. Analysis of replication precision showed that the standard methods of the histopathology laboratory, if practiced in a uniform manner, are sufficient to ensure reproducibility of these assessments. We argue that nuclear morphometry provides a standardized and reproducible framework for quantitative pathologic assessments.

Quantitation of Monoclonal Plasma Cells in Bone Marrow Biopsies in Plasma Cell Dyscrasia

Direct measurement of monoclonal plasma cell mass in bone marrow biopsies may be a useful parameter to establish in plasma cell dyscrasia. In this study monoclonal plasma cells/mm2in light chain immunoglobulin immunostained archival bone marrow sections from 22 patients in whom a diagnosis of multiple myeloma (MM) had been excluded but who had monoclonal proteins were counted by two observers at light microscopic level. There was good correlation between the counts of the two observers. The levels of monoclonal plasma cells/mm2in biopsies were not related to the % counts in the aspirates taken at the same time as the biopsies. Three of seven patients with biopsy levels in excess of the polyclonal levels in patients without plasma cell dyscrasia developed progressive MM within the observation time. Monoclonal plasma cell levels/mm2of bone marrow biopsies can be measured and they provide a useful parameter for the assessment of patients with low volume plasma cell dyscrasia. Colour figure can be viewed onhttp://www.esacp.org/acp/2003/25‐4/markey.htm.