DNA image cytometry on machine-selected breast cancer cells and a comparison between flow cytometry and scanning cytophotometry

Gross genomic damage measured by DNA image cytometry independently predicts gastric cancer patient survival

Background:

DNA aneuploidy reflects gross genomic changes. It can be measured by flow cytometry (FCM-DNA) or image cytometry (ICM-DNA). In gastric cancer, the prevalence of DNA aneuploidy has been reported to range from 27 to 100%, with conflicting associations with clinicopathological variables. The aim of our study was to compare the DNA ploidy status measured using FCM-DNA and ICM-DNA in gastric cancer and to evaluate its association with clinicopathological variables.

Methods:

Cell nuclei were isolated from 221 formalin-fixed, paraffin-embedded gastric cancer samples. DNA ploidy was assessed using FCM-DNA and ICM-DNA.

Results:

A total of 178 (80.5%) gastric cancer samples were classified as DNA aneuploid using FCM-DNA, compared with 172 (77.8%) gastric cancer samples when using ICM-DNA. Results obtained from both methods were concordant in 183 (82.8%) cases (κ=0.48). Patients with ICM-DNA diploid gastric cancer survived significantly longer than those with ICM-DNA aneuploid gastric cancer (log rank 10.1, P=0.001). For FCM-DNA data, this difference did not reach statistical significance. The multivariate Cox model showed that ICM-DNA ploidy status predicted patient survival independently of tumour-node-metastasis status.

Conclusion:

ICM-DNA ploidy status is an independent predictor of survival in gastric cancer patients and may therefore be a more clinically relevant read out of gross genomic damage than FCM-DNA.

Flow cytometry in diagnostic cytology

Flow cytometry (FCM) is a useful adjunct to cytologic examination, because the quantitative biochemical information it provides complements the morphologic information gained during visual examination. It aids in the interpretation of bladder washings, and is particularly useful for the assessment of lymphoid lesions, whether they originate from fine-needle aspiration, cerebrospinal fluid, or effusions. Optimal use of FCM frequently requires assessment of more than one parameter; simultaneous use of cell differentiation markers and nuclear DNA quantitation is often significantly more useful than either alone. Despite the utility of FCM, however, the potential for future development appears to be limited. Improvements in image cytometry allow reasonable assessment of ploidy and S-fraction to be made from specimens prepared on glass slides. Multiparameter measurements may also be accomplished with imaging techniques, which allow the further advantage of visual identification of cells with equivocal morphologic changes. The development of artificial intelligence methods for use with imaging technology has also significantly exceeded that of FCM. Finally, image cytometry is often more useful for samples with few cells. Other challenges are posed by immunocytochemical methods which compete with flow cytometry as tools for assessment of proliferation. Given the relatively high cost of FCM instrumentation, survival of FCM as an ancillary technique in cytopathology will require further technical refinements to offset the advantages currently associated with image cytometry and immunocytochemistry.

Gastric DNA content in postgastrectomy patients. Relationship to mucosal dysplasia

BACKGROUND

Gastric mucosal cellular DNA content was assessed in patients who had undergone gastric surgery for peptic ulcer disease more than 20 years previously, with the aim of examining the relationship between abnormal DNA content and gastric mucosal dysplasia, as well as determining the effect of different types of surgery on DNA content.

METHODS

Sixty-five subjects underwent upper gastrointestinal endoscopy. In each, six biopsies were taken from the stoma or antrum and graded for severity of dysplasia. Cellular DNA was quantified using a microprocessor-controlled image analysis system with a fast densitometer card on Feulgen-stained slides. DNA histograms were evaluated using the 2c deviation index (2cDI) for proliferative activity and the 4c exceeding rate (4cER) and the 5c exceeding rate (5cER) as indices of malignant potential.

RESULTS

In subjects with Billroth II operations, all the above DNA criteria were higher than in Billroth I (P < 0.05), vagotomy and pyloroplasty (P < 0.001), and controls (P < 0.0001). DNA values increased as dysplasia progressed in severity (2cDI, Rs = 0.67; 4cER, Rs = 0.61; 5cER, Rs = 0.72; respectively, P < 0.0001). Among subjects with no dysplasia, more aneuploid cells were found in the Billroth II group, (p < 0.005) compared with the other types of operation.

CONCLUSIONS

Cellular DNA content is abnormal at an early stage in dysplasia and may even predate it. Increasing values of abnormal DNA content are related to the severity of dysplasia. DNA analysis may be a useful additional tool in surveillance programs to select high-risk patients for screening.

Comparison of flow and image cytometry for DNA content analysis of fresh and formalin-fixed, paraffin-embedded tissue in breast carcinoma

DNA ploidy and S-phase fraction are considered to be prognostic variables in breast carcinoma. DNA content of 35 cases of breast carcinoma of varying histologic types and nuclear grades was analyzed by flow cytometry and image analysis in both fresh and formalin-fixed, paraffin-embedded tissue. Fresh cell and deparaffinized nuclear suspensions were used for flow cytometry. Fresh and deparaffinized tumor tissue samples were used for image analysis. The results of analysis for DNA ploidy, DNA index of DNA aneuploid Go/G1 peaks, and S-phase fraction were compared in different tissue preparations for both techniques. The two techniques produced comparable DNA ploidy results with both fresh and formalin-fixed, paraffin-embedded tissue. Sensitivity for detection of DNA aneuploidy was somewhat greater by image analysis, particularly in deparaffinized tissue. There was 89% agreement in detection of DNA aneuploidy by flow cytometry in fresh and paraffin-embedded, formalin-fixed tissue; the coefficients of variation of the DNA diploid Go/G1 peaks were much wider in the latter. In image analysis there was 91% agreement between fresh and fixed specimens. Agreement between the flow cytometry and image analysis in fresh specimens was 91%; in deparaffinized nuclear suspensions it was 94%. There is a high degree of correlation between the values of DNA index of DNA aneuploid Go/G1 peaks; the estimates of S-phase fraction are much more variable. Results also show a good correlation of the DNA ploidy with the nuclear grades.(ABSTRACT TRUNCATED AT 250 WORDS)

Interphase cytogenetics reveals a high incidence of aneuploidy and intra-tumour heterogeneity in breast cancer

The occurrence of aberrations involving chromosomes 11 and 17 in malignant tissues of breast cancer patients has not yet been studied systematically. Using fluorescence in situ hybridisation (FISH) with centromere-specific probes, we determined chromosome 11 and 17 status in interphase nuclei from primary and/or metastatic breast cancer cells. In all cancerous specimens obtained from 30 patients, FISH identified cells with clonal chromosomal abnormalities, with aneuploidy rates ranging from 6% to 92% (median 59%). There was a gain of centromeric signals for chromosome 11, most likely corresponding to hyperploidy; aberrations of chromosome 17 in specimens from 26 patients (87%) were hyperploid as well; however, four cases (13%) showed loss of chromosome 17 centromeres. All specimens contained heterogeneous aneuploid cell populations with excessive gain of signals in some cases. The pattern of aneuploidy did not appear to correlate with tumour grade/stage and was comparable in primary tumours and corresponding metastatic axillary lymph nodes, indicative of genetic instability early in tumour development. Screening with a panel of FISH probes may lead to enhanced sensitivity and specificity in detecting malignant cells, as demonstrated in this study with effusions which could not be conclusively interpreted as being malignant by cytological criteria.

Aneuploidy for chromosome 1 and overall DNA content in benign and malignant breast disease

Fluorescence in situ hybridization (FISH) with a probe for the pericentromeric region of chromosome 1 and DNA content measurements by image-analysis-based densitometry have been carried out on imprints of benign and malignant breast tissue. In general, an increase in the number of spots per nucleus was observed in the invasive carcinomas, with a large intercellular variation. In comparison with lymphocytes from controls, some cases of benign breast disease already had an increased frequency of aneusomy of chromosome 1, although they were all (near)diploid by DNA-content. However, an overall concordance between the DNA content measurements and the results of FISH was observed, although some exceptions were seen. A statistically significant correlation between the DNA index and the mean number of spots for chromosome 1 per nucleus was found. A linear discriminant analysis was applied on the data; the resulting classification of patients was most accurate when parameters describing DNA content and FISH results were combined.

Ploidy pattern and cell cycle in breast cancer as detected by image analysis and flow cytometry

Both image analysis (IA) and flow cytometry (FCM) may be applied to detect ploidy pattern and cell cycle fractions. However, they have different performance characteristics and may yield different results. The two approaches are applied in this study to 66 breast cancers: IA on imprints and FCM on fresh tissue. The percent coefficient of variation (CV) ranged from 2.0 to 7.0 (mean 5.5; SD 1.1) in IA and from 2.0 to 7.0 (mean 4.4; SD 1.1) in FCM. The values were well correlated. With regard to ploidy pattern, the agreement between the two methods was 92.4%; disagreements were due to four cases being aneuploid by IA but not detected by FCM and one case being aneuploid by IA but tetraploid by FCM. This suggests that IA is capable of detecting aneuploidy with more sensitivity than FCM. In diploid cases, the percent values of cells in G0/G1, S-phase (SPF), and G2M phase were concordant and well correlated. In aneuploid cases, IA was more sensitive than FCM in detecting aneuploid fraction as well as G2M phase, whereas FCM was more sensitive than IA in detecting SPF. A good correlation was found between the DNA indexes (DIs) obtained with the two methods.

Image cytometry: current applications and future trends

Image cytometry has numerous clinical and research applications and is particularly useful in anatomic pathology for the study of malignant lesions. Modern image systems encompass morphometry, densitometry, neural networks, and expert systems. Rapid advances in technology and the development of user-friendly systems have provided pathologists with an alternative to flow cytometry, particularly useful in the evaluation of small or hypocellular specimens. The most common current application of image cytometry is for DNA analysis, followed by quantitation of immunohistochemical staining. Newer uses under active investigation include development of expert systems that may act as diagnostic consultants in the future. Beyond DNA analysis, image cytometry holds great promise for improved tumor classification, for screening and surveillance in high-risk populations, and as a tool to improve diagnostic ability. This article discusses types of image analysis systems, specimen preparation, data acquisition, current applications in specific organ sites, and possible future applications.

Prognostic value of DNA analysis in colorectal carcinoma

BACKGROUND

Reported experiences regarding the prognostic significance of DNA content in colorectal carcinoma have been a matter of controversy.

METHODS

DNA analysis with image cytometry was performed in 137 patients with colorectal cancer. Only patients who had resection without tumor residual and who did not die postoperatively as a consequence of the operation were entered in the study. At the time of DNA analysis, neither the histomorphologic data nor the relapse-free survival time of the patients were known.

RESULTS

In this investigation the DNA content of tumor cells had no univariate or multivariate influence on the relapse-free survival time. The prognosis was dependent on the tumor localization, depth of tumor infiltration, lymph node metastasis, and grade.

CONCLUSIONS

DNA content provides no additional prognostic information in colorectal carcinoma.

The prognostic significance of the DNA content in Ewing's sarcoma: a retrospective cytophotometric and flow cytometric study

The DNA content of the cell nuclei of Ewing's sarcoma was analysed by means of cytophotometry in situ with image analysis in Feulgen-stained sections in 37 patients, and by retrospective flow cytometry according to the method of Hedley in 26 patients. Different histogram patterns were obtained: normal unimodal or bimodal DNA distributions and abnormal DNA distributions with one or two stem lines, or an abnormal DNA distribution with no stem lines. Both methods enabled us to make a distinction between two groups of Ewing's sarcomas with a different prognosis. All patients with aneuploid tumours died within 5 years after the initial diagnosis. Eleven of 19 (58%) patients with a normal DNA distribution in their tumour, as determined by cytophotometry, are still alive and in good health with a mean survival period of 7.5 years, ranging from 2 to 19 years. Of the group of patients in which flow cytometry revealed a normal DNA pattern, eight of 15 (53%) are still alive and in good health, with a mean survival period of 8 years. These results indicate that both techniques are reliable methods for obtaining prognostic information in Ewing's sarcomas. However, cytophotometry in situ yielded a better discrimination for the overall survival (P < 0.01) than did flow cytometry (P < 0.05). In 19% of the cases there was a discrepancy between the DNA histograms obtained with the two techniques. In five of 26 cases the DNA distributions were classified as normal by one method and aneuploid by the other. Tumour cell representation or selective loss of cells during enzymatic treatment may be responsible for this discrepancy.

High DNA content and prognosis in lymph node positive breast cancer. A case control study by the University of Leiden and ECOG. (Eastern Cooperative Oncology Group)

To investigate whether breast cancer cells with unusually high nuclear DNA content are associated with an adverse outcome, Eastern Cooperative Oncology Group investigators selected breast cancer trial patients who suffered an early death (ED) within two years after diagnosis to compare with other trial patients who had a survival of at least 7.5 years. Paraffin blocks of primary breast cancers were obtained from 93 evaluable patients who had been enrolled in two surgical adjuvant trials for lymph node positive (LN+) disease (T1-3N1M0). Single cell monolayer preparations from these blocks were stained with acriflavine-Feulgen and analyzed by image analysis for DNA content with the automated Leiden Television Analysis System (LEY-TAS). Standard prognostic variables (estrogen receptor (ER) status, number of lymph nodes with metastases, and size of the cancer) were compared with three DNA content characteristics: DNA ploidy status, number of nuclei with > 5C DNA content, and percent of nuclei with > 5 C. Estimates of the odds ratio in multivariate comparisons showed that ER negativity was associated with ED (p = 0.0005) and an odds ratio estimate using negative/positive of 4.87. The number of positive lymph nodes associated with ED had a p-value of 0.0005 and an odds ratio estimate of 4.63 when comparing the > 3 nodes group to the 1-3 nodes group. In contrast, the strongest association for any of the DNA content characteristics with ED had a p-value of 0.017 and an odds ratio estimate of 2.76. This power of association disappeared when stratified on ER status.(ABSTRACT TRUNCATED AT 250 WORDS)

Image cytometric DNA analysis in transitional cell carcinoma of the bladder

BACKGROUND

The current study was initiated to investigate measurable objective and reproducible characteristics that might have prognostic significance in bladder cancer.

METHODS

Tumor samples from 91 patients with primary transitional cell carcinoma (TCC) of the urinary bladder were studied by DNA image cytometry and cytogenetic analysis. Image cytometry is a more sensitive method of determining ploidy than flow cytometry, especially in tumors with a low number of aneuploid cells.

RESULTS

There was a significant difference in survival between DNA image cytometry-determined diploid and nondiploid cases. The presence of nuclei with a high DNA content indicated poor prognosis. The 2C deviation index (2CDI) also was an indicator of survival. Image cytometry-determined factors also were found to be strong predictors of progression-free survival. In multivariate analysis, 2CDI was the only cytometric parameter with an independent but weak correlation with survival. In multivariate analysis, none of the cytometric parameters had an important contribution to prediction of progression-free survival. In superficial tumors (Ta and T1), 2CDI appeared to be the most important independent predictor of survival. With respect to progression-free survival, tumors with a high mitotic index proved to have a worse prognosis.

CONCLUSIONS

Parameters determined by DNA image cytometry appear to be valuable in predicting survival and progression-free survival and may be useful in addition to the classic parameters of stage and grade, especially in superficial TCC.

Neural Network Analysis of DNA flow cytometry histograms

A pattern recognition system based on Neural Network Analysis, a form of artificial intelligence, was used to search DNA flow cytometry histograms for features that correlated with breast cancer patients' risk of relapse. DNA flow cytometry histograms and clinical follow-up information from 796 breast cancer patients were used to train a Neural Network to predict the clinical outcome of patients in a separate independent set of 794 patients. Median follow-up in this patient data base was short, 23 months. Neural Network Analysis resulted in a model that evaluated DNA flow cytometry histograms differently than conventional analysis, which categorizes the histograms by ploidy and S-phase fraction. Neural Network Analysis appeared to identify low risk and high risk subsets of patients as accurately as conventional analysis. Neural Network Analysis placed heavy emphasis on the region to the right of the diploid G2/M peak, where a subpopulation of nuclei with high DNA content is seen even in many histograms scored as diploid by conventional techniques. The number of nuclei in this region was found to be a powerful predictor of patient outcome, and multivariate analysis showed that the number of nuclei in this region and the S-phase fraction both were independently predictive of relapse. This pilot study suggests that conventional analysis (based on a mechanistic interpretation of regions in flow cytometry histograms) might be used in conjunction with and improved by pattern recognition systems or insights derived from them.

Method for counting mitoses by image processing in Feulgen stained breast cancer sections

This study describes an image processing method for the assessment of the mitotic count in Feulgen-stained breast cancer sections. The segmentation procedure was optimized to eliminate 95-98% of the nonmitoses, whereas 11% of the mitoses did not survive the segmentation procedure. Contour features and optical density measurements of the remaining objects were computed to allow for classification. Twelve specimens were analyzed, nine used to serve as a training set, and three put aside for later use as independent test set. The fully automatic image processing method correctly classified 81% of the mitoses at the specimen level while inserting 30% false positives. The automatic procedure strongly correlated with the interactive counting procedure (r = 0.98). Although the fully automatic method provided satisfactory results, it is not yet suited for clinical practice. The automated method with an interactive evaluation step gave an accurate reflection of the mitotic count showing an almost perfect correlation with the results of the interactive morphometry (r = 0.998). Therefore this semiautomated method may be useful as prescreening device.

A comparative study of DNA ploidy in 115 fresh-frozen breast carcinomas by image analysis versus flow cytometry

BACKGROUND

Qualitative and quantitative analysis of cellular DNA content may be clinically useful in the prognostic evaluation of certain types of malignant tumors, including breast carcinoma. Flow cytometric (FCM) analysis has been the most frequently used procedure for DNA analysis, but it requires a reasonably large tissue sample. Computer-based image analysis (IA) now allows imprint, cytospin, and needle aspiration smear preparations and other small tissue samples to be used.

METHODS

To resolve concern about the diagnostic efficacy of small tissue samples in the use of IA, the authors performed a comparative study of FCM analysis and IA using 115 fresh-frozen breast carcinomas. Feulgen-stained imprint preparations for IA and single-cell suspensions from the same fresh-frozen tissue for FCM analysis were used, and the respective histograms were compared.

RESULTS

The results were concordant in 90.4% (104 of 115) of the cases, but 11 specimens yielded discordant data. IA provided histograms with a somewhat lower resolution and a relatively high coefficient of variation for the G0/G1 peak, thus rendering occasional tumors, which were near-diploid aneuploid by FCM analysis (four cases), not amenable to diagnosis by aneuploid characterization. In three additional cases, FCM analysis showed aneuploid hyperdiploid (two cases) and multiploid (one case) histograms, but IA only demonstrated a diploid peak. Conversely, in four other cases, aneuploid peaks were recognized only by IA.

CONCLUSIONS

Computerized IA has significant advantages over FCM analysis, including lower cost, the ability to analyze very small specimens, the capability of detecting rare high ploidy cells, the capacity to classify cellular populations according to specific morphologic type, and the fact that no destructive enzyme or chemical digestion is required for specimen preparation, thereby preserving the integrity of fragile cells.

The study of endocrine tumors by flow and image cytometry

Both DNA flow and image cytometry are methods that can be used for the quantitative determination of cellular DNA content. Objective, quantitative analysis of cellular morphology can also be obtained using image cytometry. Data thus generated have been shown to be of diagnostic and prognostic use in the study of many solid tumors and would be of particular value in the evaluation of endocrine tumors that show a poor correlation between their histology and biological behavior. The main application of these techniques to endocrine tumors has been in the analysis of thyroid nodules, although a limited number of studies of parathyroid, pituitary, adrenal, and pancreatic neuroendocrine tumors and tumors of the dispersed neuroendocrine system have been reported. Review of these studies shows that in the endocrine organs DNA and morphometric measurements have a very limited role in the diagnosis of individual cases, but are important as prognostic variables. The high incidence of abnormal DNA content in histologically benign lesions of the endocrine glands has important biological implications. Further investigation of this phenomenon may help to elucidate the process of endocrine tumorigenesis.

Quantitative DNA analysis and proliferation in breast carcinomas. A comparison between image analysis and flow cytometry

The DNA content and proliferation in 100 invasive breast carcinomas were evaluated by computerized image analysis (IA) and flow cytometry (FCM). For DNA content, image analysis of Feulgen-stained slides of fresh tumor imprints were compared with flow cytometry of propidium iodide-stained disaggregated fresh tumor tissue. The DNA indices obtained by the two methods showed close correlation by linear regression analysis (r = 0.89, p less than .001). There were 44 (44%) diploid and 56 (56%) aneuploid tumors. There was agreement between the two methods in detection of aneuploidy in 81% of tumors. Image analysis required smaller tissue samples, permitted direct visualization and selection of tumor cells, and was more sensitive in detecting tetraploid and highly aneuploid cell populations. In contrast, flow cytometry histograms provided better resolution, and were more effective in detecting multiploid tumors and near-diploid aneuploid tumors. Aneuploidy was significantly related to various adverse prognostic parameters, namely, negative estrogen receptor, high mitotic rate, high histologic and nuclear grades. Proliferation was evaluated by measuring the FCM S phase fraction (SPF), and by image analysis quantitation of immunohistochemical staining using Ki-67 monoclonal antibody. SPF and Ki-67 count showed modest correlation (r = 0.42). Both SPF and Ki-67 count were significantly related to the mitotic rate, histologic and nuclear grades. Our results indicate that the two methods provide comparable results, but offer individual advantages and are complementary techniques in analyzing DNA ploidy and proliferation in breast carcinomas.

DNA ploidy studies of benign and malignant tumours: comparison of flow cytometry and image analysis techniques using two types of cytological specimen

DNA ploidy studies were carried out on Feulgen stained smears and cytocentrifuge preparations from 35 malignant tumours and four benign neoplasms using the CAS image analyser. The smears were prepared from scrapings from fresh tumour tissue whereas the cytocentrifuge preparations were prepared from single nuclear suspensions from paraffin-embedded cell blocks from the same tumour. Histograms obtained by image analysis of the tumour scrapes were compared with those obtained on the cytocentrifuge preparations. Concordant results were obtained in four benign tumours (100%) and 32 malignant tumours (91%). The results obtained by image analysis were also compared with results obtained by flow cytometry of the tumour tissue. Discordant results were obtained for three malignant tumours. Possible reasons for the discrepancy include sampling error, tumour heterogeneity and selective loss of cell populations during processing.

DNA ploidy level and S-phase fraction as prognostic factors in breast cancer

Imprint smears from sixty cases of breast cancer made after mastectomy were stained by the Feulgen method and the nuclear DNA content measured by a cytofluorometer equipped with an incident illumination system. After logarithmic transformation of the fluorescence intensity, the ploidy level and S-phase fraction (SPF) were calculated with a microcomputer and the correlation between the ploidy level or SPF and the clinicopathological prognostic factors studied. Patients with tumors of a larger diameter and more extensive lymph node involvement had higher levels of ploidy and SPF and the ploidy level in the metastatic lymph nodes was higher than that in the primary lesion. Moreover, a significant increase in SPF was observed in the metastatic lymph nodes and a high ploidy level found to be associated with tumors having a negative estrogen receptor. When the tumors were divided into a diploid group and an aneuploid group, the diploid group showed a significantly better prognosis than the aneuploid group, in 6-year survival. Similarly, the groups in which SPF was less than 20.0 per cent had significantly better prognoses than the group in which SPF was 20.1 per cent or more. These prognostic factors were evaluated with Cox's proportional hazard model and a significant correlation observed in lymph node status, ER status, ploidy level and S-phase fraction. It was thus concluded that ploidy level and SPF are important and independent prognostic factors for predicting the postoperative course of breast cancer patients.

Cytophotometry in tumor pathology. A critical review of methods and applications, and some results of DNA analysis

In tumor pathology the quantitation of cellular substances can be of diagnostic value. Microscope cytophotometry and digital image analysis and, on the other hand, flow cytometry are supplementary methods for measuring, each with a typical spectrum of application. The methods are predominantly used for DNA analysis: Static and image cytophotometry are applicable to cytologic and histologic slides preferably for identifying stem lines in tumors of heterogenous morphology and in merely circumscribed lesions (e.g., precancerous lesions). On the other hand, sampling errors due to preselection, and the often low number of cells actually measured, may preclude the possibility of exact cell cycle analysis. This is, in fact, an important additional option of flow cytometry resulting from the high resolution of DNA histograms, which is explained by the large number of cells that can be measured in a short period. Sampling errors in flow cytometry may result from the preparation of single cell suspensions which in certain tumor entities may suppress a varying amount of particularly fragile cells or nuclei. The prognostic significance of DNA ploidy, stem line heterogeneity and S-phase fraction is clearly described in quite a number of tumor entities. Independent of its prognostic value, the cytometric identification of stem lines might be particularly useful in the follow-up of tumor patients, where it may indicate the effectivity of systemic therapy. The development of therapeutic concepts is aptly supported by flow cytometric cell cycle analysis which helps to assess the in vitro effect of combined cytostatics on the proliferative process. Moreover, multiparameter analysis of biopsy samples may provide greater accuracy in characterising individual tumor stem lines and may furthermore help to develop improved protocols for the therapy of solid tumors.

Comparison between image and flow DNA cytometry in non-Hodgkin's lymphomas

To assess the reliability of DNA estimation in cytological material, Feulgen lymph node imprints from 22 cases of malignant non-Hodgkin's lymphomas were examined by image cytometry (ICM) for both ploidy and cell kinetics, and the results obtained were compared with flow cytometry (FCM). The DNA distribution pattern was less accurate with ICM than with FCM; however, a high correlation was found between proliferative indices (r = 0.91) and between aneuploidy rates (agreement in about 86% of the cases) determined by FCM and ICM. Moreover, DNA tetraploid (or near-tetraploid) stem lines were more easily detected by ICM, due to the morphological selection of lymphomatous cells. The proliferation rate and the aneuploidy frequency according to morphological classification were in agreement with larger, previously reported studies with FCM. Therefore, ICM appears to supply additional complementary information to that obtained with FCM, particularly for the study of heterogeneous cell populations, which may be usefully applied to refine the large cell lymphoma subclassification.

Automated cell analysis for DNA studies of large cell populations using the LEYTAS image cytometry system

Image cytometry by means of LEYTAS features analysis of both fresh and archival cellular material. Although not as accurate in ploidy determination as flow cytometry, LEYTAS cytometry incorporates extensive artefact rejection algorithms, thereby allowing detection of low frequency cells. This feature is very useful for the search of rare cells, as e.g. in cervical screening, or for the quantitation of the number of high DNA content cells in the total cell sample. LEYTAS main components are an automated microscope (Autoplan) and a Modular Image Analysis Computer (MIAC), both from Wild Leitz (W-Germany). This paper discusses LEYTAS instrumentation and cell analysis by means of programs especially written for LEYTAS.

Value of DNA image cytometry in the prediction of malignant change in Barrett's oesophagus

DNA image cytometry was performed on Feulgen stained sections from 91 biopsies obtained during prospective endoscopic surveillance of 55 patients with Barrett's oesophagus. Aneuploid cells were detected in specimens from six of these patients. Four subsequently developed dysplasia and adenocarcinoma but, in the other two, biopsies had been reported as showing specialised epithelium only, with no apparent dysplasia and no evidence of malignancy on clinical follow up to date. In two of the four patients who subsequently developed carcinoma, aneuploid cells were only found in biopsies showing overt dysplasia or carcinoma but in the two other patients aneuploid cells were present in biopsies taken early in the clinical course before any dysplasia had been identified on the original reports. The presence of aneuploid cells on cytometry of these 'benign' biopsies allowed us, on histological review, to identify areas of atypia which were interpreted as mild dysplasia. In this series aneuploidy was always associated with some morphological abnormality varying from mild dysplasia to frank carcinoma. Aneuploid cells were not shown in material from one patient who had an oesophagectomy for dysplasia or in biopsy material from four patients showing 'indefinite dysplasia'. DNA cytometry combines an objective assessment of epithelial atypia with the advantage of detecting rare cellular aneuploidy and the ability to correlate these events with morphology. It should assist in the more accurate diagnosis of dysplasia and prove useful in identifying those patients with Barrett's oesophagus who are at greater risk of subsequently developing malignancy.

Flow cytometric measurements of DNA and other cell components in human tumors: a critical appraisal

Fundamental principles of flow cytometry with emphasis on DNA measurements and cell cycle analysis in human cells and tissues are summarized. Some of the pitfalls of cell preparation techniques and histogram interpretation are discussed at length. While consensus has been reached for some organs and tumors that DNA quantitation by flow cytometry (or image cytometry) may be of prognostic value, for most cancers studied to date the information remains incomplete. Thoroughly lacking are well-structured prospective studies because retrospective studies, while suggestive, may not necessarily be of the same value. Potential usefulness of other tumor markers is briefly discussed. Many fundamental questions concerning definitions of "diploid" and "aneuploid" tumors have not been satisfactorily settled. While the goal of "objective measurements" is worthy of further pursuit, the interpretation of results is often highly subjective. The biologic reasons for behavioral differences between diploid and aneuploid tumors are still totally obscure.

Flow cytometric analysis of stemline heterogeneity

The stemline heterogeneity of malignant tumors is closely connected with tumor aneuploidy. Both features can be characterized by either chromosome analysis or DNA cytophotometry. DNA analysis may be performed either by single cell photometry or by flow cytometry, of which the respective advantages and drawbacks are presented. Preliminary results of flow cytometric DNA analysis in malignant neoplasms are discussed; the possibilities of multiparametric measurement for quantitative analysis of various biochemical and antigenic properties in DNA stemlines are considered.

Improving the prognostic value of DNA flow cytometry in breast cancer by combining DNA index and S-phase fraction. A proposed classification of DNA histograms in breast cancer

To optimize the prognostic value of DNA flow cytometry in breast cancer the authors calculated several parameters from the DNA histogram, including the DNA index, the size and number of aneuploid peaks as well as S-phase and G2/M-phase cell cycle fractions. Of these, DNA index and S-phase fraction (SPF) proved to be the most valuable prognostic indices. DNA aneuploidy was associated with a three-fold risk of death as compared to DNA diploidy (P less than 0.0001). The highest risk of death was associated with hypertetraploid (greater than 2.20) DNA index, whereas a tetraploid DNA index (1.80-2.20) was associated with a relatively low risk. The SPF had significant additional prognostic value in both DNA diploid (P = 0.0002) and DNA aneuploid (P = 0.02) tumors. By combining DNA index and SPF the authors defined three types of DNA histograms, which were associated with favorable, intermediate, and poor prognosis of the patients. DNA diploidy together with low (less than 7%) SPF (type I DNA histogram) was associated with very favorable prognosis, whereas DNA aneuploidy with high DNA index (greater than 2.20) or high (greater than 12%) SPF (type III DNA histogram) was related to the worst prognosis with approximately eight-fold relative risk of death. In a Cox multivariate regression analysis the type of DNA histogram was an independent and most powerful prognostic indicator in breast cancer. The other independent factors in the Cox analysis were primary tumor size, nodal status, and progesterone receptor status.

Automated screening for micrometastases in bone marrow smears

It is possible to detect micrometastases in primary breast cancer using immunocytochemical staining of bone marrow smears. However, using the light microscope the procedure is time-consuming and laborious because such cells occur rarely (less than 1 in 10,000). Using an image analysis system, the Leytas machine, and a specially prepared reproducible slide it has been possible to automate the technique. A 100% concordance was found between the machine and the light microscope in the identification of slides containing moderate to high numbers of tumour cells in bone marrow, and in those containing no tumour cells. However, in those slides containing low numbers of tumour cells (1-10 tumour cells/10(6) normal bone marrow cells) the sensitivity was decreased to 91%. In the presence of non-specific staining the false positive rate was increased from 0% to 22%. This method represents a potential improvement in the assessment of an important clinical staging procedure.

Comparison of extent of disease and morphometric and DNA flow cytometric prognostic factors in invasive ductal breast cancer

In 65 patients with primary invasive ductal breast carcinoma the relation between classic prognosticators describing the extent of disease (lymph node metastases and tumour size) and newer promising morphometric and DNA flow cytometric prognostic factors was studied. There was no relation between DNA ploidy, lymph node state, and tumour size. Tumours with a mitotic activity index of more than 10 were predominantly DNA aneuploid (61%) compared with those with a mitotic activity index of less than 10 which showed a DNA aneuploid pattern in 27%. The strongest prognosticator, the morphometric prognostic index (a multivariate combination of mitotic activity index, tumour size, and lymph node state) correlated positively with the DNA index in 63% of the cases (p = 0.038). Thus there was a discrepancy between the morphometric and DNA flow cytometric prognostic variables in 37% of the cases. These results indicate that morphometric and flow cytometric analysis may provide additional information on the prognosis in primary breast cancer.

Flow cytometry and Feulgen cytophotometry in evaluation of effusions

Fifty-eight effusions (42 pleural and 16 ascitic fluids) from patients with and without cancer were analyzed by conventional cytology and the results compared with DNA patterns generated by flow cytometry of 10(4) nuclei and several modes of Feulgen cytophotometry. In 31 patients (24 without evidence of cancer and seven with history of cancer and cytologically negative fluids), the fluids were diploid by flow cytometry. One fluid with atypical cells from a lymphoma suspect was also diploid. Flow cytometry of 26 cytologically cancerous fluids disclosed aneuploid DNA patterns in 16 and diploid patterns in ten. Feulgen cytophotometry of 11 of these fluids (three aneuploid, eight diploid) was performed on nuclear preparations identical to those used in flow cytometry and on restrained smears used for visual analysis. The analysis was performed in two modes: as a study of 500 sequential nuclei in an automated system, mimicking flow cytometry, and visually selected large, presumably malignant nuclei. In nine of the 11 cases, the DNA content of visually selected cancer cells was aneuploid, even though this DNA pattern was not evident in the analysis of 500 sequential cells. In two cases, both diploid by flow cytometry, the Feulgen analysis confirmed the presence of cancer cells in the diploid range. In samples of 10(4) nuclei representing a mixed population of cells occurring in effusions, the presence of aneuploid cancer cells may not be disclosed by conventional flow cytometry. A larger sample of cells, a detailed analysis of DNA histograms, and perhaps sorting of select cells in the hypertetraploid range, may prove essential before flow cytometry can be accepted as a diagnostic tool in the laboratory in the assessment of effusions.

DNA ploidy and survival in breast cancer patients

Flow cytometric DNA ploidy measurements using frozen or deparaffinized tumor specimens were performed on 565 primary breast cancers from patients treated in the period 1975-1984. Twenty-nine percent of the cases were diploid, 61% had a single aneuploid stemline, and 10% were multiploid. Aneuploid tumors more often had negative estrogen receptor values than diploid tumors, but no significant correlation was found between ploidy class and TNM stage. Patients with more than ten positive axillary lymph nodes had predominantly aneuploid tumors. Overall and distant relapse-free survival were higher for patients with diploid tumors and low-aneuploid tumors. Stratification of the patients according to degree of lymph node involvement, TNM stage, and menopausal stage showed that the prognostic effect of aneuploidy was apparent predominantly in patients with locally advanced disease. Postmenopausal node-positive patients with diploid tumors had a significantly better prognosis than those with aneuploid tumors, but this difference was not found for the comparable premenopausal group. Multivariate analysis with the Cox proportional hazards model indicated that ploidy is an additional, independent prognostic factor in postmenopausal patients.

Image analysis combined with quantitative cytochemistry. Results and instrumental developments for cancer diagnosis

This paper describes the application of image analysis combined with a quantitative staining method for the analysis of cervical specimens. The image analysis is carried out with the Leyden Television Analysis System, LEYTAS, of which two versions are described. LEYTAS-1 as well as LEYTAS-2 have both been designed with a high degree of flexibility and interaction facilities. A much wider range of image analysis programs is however, possible with LEYTAS-2, enabling many applications. LEYTAS-1, the earlier version, consists of a Leitz microscope with automated functions, a TV camera, the Texture Analysis System (TAS, Leitz), a four-bit grey value memory and a minicomputer (PDP 11/23). Using this instrumentation 1,500 cervical smears prepared from cell suspensions and stained with acriflavin-Feulgen-Sits have been analysed in a completely automated procedure. Image transformations working in parallel on entire fields, have been used for cell selection and artefact rejection. Resulting alarms, consisting of selected single cells and non-rejected artefacts are stored in the grey value memory, which is displayed on a TV monitor. This option allows visual interaction after the machine diagnosis has been made. The machine diagnosis was correct in 320 out 321 specimens with a severe dysplasia or more serious lesion. The false positive rate in 561 morphologically negative specimens (normal and inflammation) was 16% (machine diagnosis). Visual interaction by subtracting the visually recognized false alarms from the total number of alarms reduces the false positive rate to 11%.(ABSTRACT TRUNCATED AT 250 WORDS)