Activated macrophages containing tumor marker in colon carcinoma: immunohistochemical proof of a concept.

The presence of carcinoembryonic antigen (CEA)-containing activated macrophages has been demonstrated in peripheral blood from patients with colorectal carcinoma. Macrophages migrate from the circulation into the tissue, phagocytose debris, and return to the bloodstream. Hence it seems likely that activated macrophages containing tumor debris, i.e., tumor marker, are present in the stroma of colorectal carcinoma. After phagocytosis, they could follow a hematogenic or lymphogenic route to the peripheral blood. The aim of this study is to assess the presence of tumor marker-containing activated macrophages in the stroma of colon carcinoma and in regional lymph nodes. From 10 cases of colon carcinoma, samples of tumor tissue and metastasis-free lymph nodes were cut in serial sections and stained for CD68 to identify macrophages and for CEA, cytokeratin, or M30 presence. Slides were digitalised and visually inspected using two monitors, comparing the CD68 stain to the tumor marker stain to evaluate the presence of tumor marker-positive macrophages. Macrophages containing tumor marker could be identified in tumor stroma and in metastasis-free regional lymph nodes. The distribution varied for the different markers, CEA-positive macrophages being most abundant. The presence of macrophages containing tumor marker in the tumor stroma and lymph nodes from patients with colon carcinoma could be confirmed in this series using serial immunohistochemistry. This finding supports the concept of activated macrophages, after phagocytosing cell debris, being transported or migrating through the lymphatic system. These results support the potential of tumor marker-containing macrophages to serve as a marker for diagnosis and follow-up of colon cancer patients.

Performance evaluation of the Abbott CELL-DYN Ruby and the Sysmex XT-2000i haematology analysers.

Two mid-range haematology analysers (Abbott CELL-DYN Ruby and Sysmex XT-2000i) were evaluated to determine their analytical performance and workflow efficiency in the haematology laboratory. In total 418 samples were processed for determining equivalence of complete blood count (CBC) measurements, and 100 for reticulocyte comparison. Blood smears served for assessing the agreement of the differential counts. Inter-instrument agreement for most parameters was good although small numbers of discrepancies were observed. Systematic biases were found for mean cell volume, reticulocytes, platelets and mean platelet volume. CELL-DYN Ruby WBC differentials were obtained with all samples while the XT-2000i suppressed differentials partially or completely in 13 samples (3.1%). WBC subpopulation counts were otherwise in good agreement with no major outliers. Following first-pass CBC/differential analysis, 88 (21%) of XT-2000i samples required further analyser processing compared to 18 (4.3%) for the CELL-DYN Ruby. Smear referrals for suspected WBC/nucleated red blood cells and platelet abnormalities were indicated for 106 (25.4%) and 95 (22.7%) of the XT-2000i and CELL-DYN Ruby samples respectively. Flagging efficiencies for both analysers were found to be similar. The Sysmex XT-2000i and Abbott CELL-DYN Ruby analysers have broadly comparable analytical performance, but the CELL-DYN Ruby showed superior first-pass efficiency.

The value of the Thomas-plot in the diagnostic work up of anemic patients referred by general practitioners.

In patients with inflammatory conditions, diagnosing classic iron deficiency or anemia of chronic disease is challenging. In this study, we assessed the diagnostic value of the so-called Thomas'-plot [soluble transferrin receptor (sTfR)/log ferritin (sTfr/log Ferr) and the reticulocyte hemoglobin equivalent (Ret-HE)] in the anemia work up of patients referred by general practitioners. During July 2008-March 2009, 337 consecutive patients were included because of lowered Hb values. The laboratory results of the first 133 consecutive patients were used to determine the cut-off values for the diagnostic plot. The laboratory results of these patients were assessed and interpreted independently by two investigators, blinded from sTfR/log Ferr and Ret-HE values. The following 204 patients were used to test the plot in practice. In 32% of the first 133 patients, no indication of the cause of anemia could be found. However, when using the diagnostic plot in the following 204 patients, this fraction decreased to 14%. The 'Thomas'-plot is of diagnostic value for distinguishing functional iron deficiency from classic iron deficiency in a patient population referred by general practitioners.

Detecting prostate cancer by intracellular macrophage prostate-specific antigen (PSA): a more specific and sensitive marker than conventional serum total PSA.

BACKGROUND: Serum prostate-specific antigen (PSA) is a standard method and a widely used marker for prostate cancer, but it has a poor specificity for early detection. Herein we demonstrate that intracellular macrophage PSA (imPSA) enables screening and differentiation between benign and malignant prostate disease. MATERIALS AND METHODS: The efficacy of intracellular macrophage PSA in circulating and tissue macrophages was therefore investigated in a double-centre study of 38 prostate cancer patients and 36 healthy controls by fluorescent-activated cell sorting analysis and immunohistology. RESULTS: Both methods uncovered the existence of PSA-positive macrophages specific for patients with prostate cancer. In addition, we demonstrate the superiority of our new test over standard serum total PSA in a blinded double-centre trial. ImPSA had a marked higher sensitivity and specificity than serum total PSA (imPSA: sensitivity 92%, specificity 92%, positive predictive value 92%; serum total PSA: sensitivity 79.5%, specificity 87.5%, positive predictive value 26.8%). CONCLUSION: In this study, we demonstrate that imPSA is a new prostate cancer screening method that is highly sensitive and more specific than standard PSA testing.

Elevated apoptosis-associated cytokeratin 18 fragments (CK18Asp386) in serum of patients with chronic liver diseases indicate hepatic and biliary inflammation.

OBJECTIVES: During apoptosis, intermediate filament protein cytokeratin 18 (CK18) is cleaved by caspases at Asp396 which can be specifically detected by the monoclonal antibody M30 (M30-antigen). DESIGN AND METHODS: M30-antigen serum levels were analyzed in 76 chronic liver diseases (CLD) patients and 62 healthy controls. RESULTS: M30-antigen levels were significantly elevated in CLD patients (median 296.3 U/L) compared with healthy controls (median 153.5 U/L, P<0.001) and increased with disease severity (Child-Pugh or MELD score). M30-antigen correlated with aminotransferase activities and parameters indicating cholestasis such as bile acids. Highest serum M30-antigen was associated with histologically confirmed severe intrahepatic cholestasis (median 599.1 U/L) or biliary duct inflammation (median 648.0 U/L). Furthermore, in contrast to patients with liver cirrhosis, presence of hepatocellular carcinoma was associated with elevated M30-antigen in patients without cirrhosis. CONCLUSION: Serum M30-antigen levels are elevated in CLD and correlate with hepatic inflammation as well as cholangitis and cholestasis.

Determination of threshold values for determining the size of the fraction of steroid hormone receptor-positive tumor cells in paraffin-embedded breast carcinomas.

BACKGROUND: For 4 years we used a multiparameter DNA flow cytometric (MP-FCM) technique to assess steroid hormone receptor expression in the diagnostic workup of routinely processed formalin-fixed, paraffin-embedded breast carcinomas as an alternative to immunohistochemistry (IHC) for the quantification of hormone receptor-positive cells. In all cases a positive fraction of hormone receptor-expressing epithelial cells was detected. This observation raised the question of what the cutoff value might be to distinguish receptor-negative from receptor-positive tumors. METHODS: In our search for a possible threshold value of positivity for estrogen receptor (ER) and progesterone receptor (PR) in MP-FCM, we developed four steps. First, we compared IHC results in our own laboratory with the results obtained by MP-FCM on a small series of breast tumors (n = 42). Second, after collecting our first 843 tumors, we made a comparison with the literature of the distribution of receptor positivity according to age classes. Third, using the most likely threshold that resulted from this comparison, we compared a subset of 340 node-negative tumors for their combined ER/PR profiles with the data from a similar group of node-negative tumor cases from the National Cancer Institute's Surveillance, Epidemiology and End-Result (SEER) study. Fourth, with the results of these comparisons, we prospectively collected IHC data and MP-FCM results of the same tumor samples for a period of 1 year. In this way, we collected data for an additional 180 tumors. RESULTS: The first step in this process resulted in an previous publication where 20% of steroid hormone receptor-positive cells seemed to be an acceptable cutoff point for positivity. However, the second step provided the best correlation at approximately 35% of ER reactive cells in the cytokeratin-positive cell population. With this cutoff, the distribution of combined ER/PR profiles in our patient population of node-negative breast cancers also showed a distribution similar to the data from the SEER study. The fourth step, using the 35% threshold value, resulted in a good correlation (r = 0.85, P < 0.0001) for ER and PR between IHC and MP-FCM in the 180 tumors investigated. CONCLUSION: By comparing in-house data with those from large external data collections in the literature, a threshold percentage can be defined that distinguishes steroid hormone receptor-negative from hormone receptor-positive tumors. As a result, information about DNA content and cell cycle distribution can be obtained. This observational study provides additional support to our opinion that MP-FCM is an alternative for IHC determination of ER and PR positivity. It is more objective and quantification can be done more appropriately. The additional value of this approach is that we generate continuous variables of ER/PR content instead of categorical classes, which can be used at different threshold levels for evaluation of clinical relevance.

Multiparameter flow cytometry in the diagnosis of a gynaecologic double tumor: a case report.

PURPOSE: An uncommon clinical presentation of metastatic tumor will often lead to additional diagnostic examinations. The patient of the present study was known to have endometrial cancer which was thought to be limited to the endometrium. Three months postoperatively, she developed ascites due to spread of the tumor, which is rarely seen in low-stage endometrial cancer. METHOD: Multiparameter flow cytometry using both cell phenotype information and DNA ploidy was performed. RESULTS: Retrospectively, the patient was diagnosed as having a DNA-diploid epithelial tumor of the endometrium as well as a DNA-aneuploid epithelial tumor in the left fallopian tube. It was shown that 3 months after primary surgery she developed ascites caused by metastatic tumor from the primary fallopian tube cancer. CONCLUSION: The complete diagnosis was made using multiparameter flow cytometry which, at present, is not routinely applied in gynecologic pathology.

An immunohistochemical study of the clearance of apoptotic cellular fragments.

We investigated the distribution and fate of apoptotic bodies during human development and in the adult, using an antibody (M30) that recognizes a neo-epitope formed early in the apoptotic cascade by caspase cleavage of cytokeratin 18. In the fetus, we found extensive accumulation of M30-positive, non-phagocytosed fragments in the red pulp of the spleen, subcutaneous and submucosal vessels, the interstitium of the lung, and the glomerular mesangium of the kidneys. In the liver, M30-immunoreactive fragments were found inside macrophages in the sinusoids. The number of these fragments and the intensity of the immunostaining increased with the gestational age of the fetus. In the adult, M30-positive fragments were barely detectable in normal tissues. However, many pathological situations, including both chronic degenerative processes and metastatic cancer, were associated with accumulation of M30-positive fragments in the red pulp of the spleen. In the liver and kidney, no fragments could be detected. Remarkably, 13 of the 16 patients with metastasized cancer showed pronounced accumulation of M30-positive fragments containing hematoxylin-reactive material in the red pulp of the spleen. In the non-cancerous cases, such DNA-containing fragments were only seen in 9 of 94 cases. The results show that when apoptotic activity is high, as during development in the fetus or during metastasis and other pathological processes in the adult, the phagocytic clearance of apoptotic bodies can be overloaded. These apoptotic fragments then accumulate in the spleen. The visual detection of apoptotic fragments is concluded to reflect increased cell turnover.

Multiparameter flow cytometry as a tool for the detection of micrometastatic tumour cells in the sentinel lymph node procedure of patients with breast cancer.

AIM: To investigate whether multiparameter flow cytometry (MP-FCM) can be used for the detection of micrometastasis in sentinel lymph nodes (SLNs) in breast cancer. METHODS: Formalin fixed, paraffin wax embedded sentinel lymph nodes (n = 238) from 98 patients were analysed. For each lymph node, sections for haematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) for cytokeratin (MNF116) were cut at three levels with a distance of 500 microm. The intervening material was used for MP-FCM. Cells were immunostained with MNF116, followed by an incubation with fluorescein isothiocyanate (FITC) labelled goat antimouse immunoglobulin. DNA was stained using propidium iodide. From each lymph node 100,000 cells were analysed on the flow cytometer. RESULTS: Thirty eight of the 98 patients with breast carcinoma showed evidence of metastatic disease in the SLN by one ore more of the three methods. In 37 of 38 cases where metastatic cells were seen in the routine H&E and/or IHC, more than 1% cytokeratin positive cells were detected by MP-FCM. In 24 patients, metastatic foci were more than 2 mm (macrometastasis) and in 14 these foci were smaller than 2 mm (micrometastasis). In three of these 14 cases, MP-FCM revealed positive SLNs, although this was not seen at first glance in the H&E or IHC sections. After revision of the slides, one of these three remained negative. However, MP-FCM analysis of the cytokeratin positive cells showed an aneuploid DNA peak, which was almost identical to that of the primary breast tumour. Duplicate measurements, done in 41 cases, showed a 99% reproducibility. In five of 14 patients with micrometastasis, one or two metastatic foci were found in the non-SLN. However, in 15 of 24 macrometastases multiple non-SLNs were found to have metastatic tumour. All micrometastases except for the remaining negative one mentioned above showed only diploid tumour cells, despite the fact that their primary tumours contained both diploid and aneuploid tumour cells. In primary tumours with more than 60% aneuploid cells, predominantly aneuploid macrometastasis were found, whereas diploid primary tumours only showed diploid micrometastases or macrometastases in their SLN. Aneuploid SLN macrometastases were associated with non-SLN metastases in five of seven patients, whereas diploid cases showed additional non-SLN metastases in only seven of 16 patients. CONCLUSION: In all cases, MP-FCM was sufficient to detect micrometastatic tumour cells in a large volume of lymph node tissue from SLNs. In some cases it was superior to H&E and IHC staining. Approximately 30% of SLN micrometastases are accompanied by additional non-SLN metastases. The size of the aneuploid fraction (> 60%) in the primary tumour may influence the risk of having both SLN and non-SLN metastases.

Steroid receptor heterogeneity in relation to DNA index in breast cancer: a multiparameter flow cytometric approach on paraffin-embedded tumor samples.

Steroid hormone (estrogen and progesterone) receptor (ER and PR) status at the time of breast carcinoma surgery is used as a marker for hormone dependency to guide adjuvant therapy. In a significant number of cases a discrepancy exists between the detected number of hormone receptors and the response to hormonal therapy. One of the explanations for this could be intratumoral heterogeneity. Our objective was to investigate the heterogeneity of steroid hormone receptor expression in breast cancer by using multiparameter flow cytometry (MP-FCM) on routinely processed formalin-fixed, paraffin-embedded tumors. A series of 232 routinely processed breast carcinomas were analyzed using a recently developed technique for the isolation of single cells from paraffin-embedded material. After dewaxing and rehydrating, 50-microm thick sections were heated for 2 hours at 80 degrees C in a citrate solution. Single-cell suspensions were prepared by a short pepsin digestion. The obtained single-cell suspensions were immunostained simultaneously for cytokeratin and ER or PR. Finally, DNA was stained using propidium iodide, after which the samples were analyzed on a flow cytometer. The fractions of ER- and PR-positive cells were determined in the total, as well as the G0 /G1 fraction of the diploid, and in case of nondiploid tumors, also in the G0 /G1 fraction of the aneuploid cell population. Of 232 cases, 88 (38%) were diploid, 38 (16%) were tetraploid, and 106 (46%) were aneuploid. In the diploid tumors the mean fraction of ER- and PR-positive cells was 81% and 76%, respectively. The ER- and PR-positive fractions in the total cytokeratin-positive fraction decreased significantly in the tetraploid (56% and 55%, respectively) and aneuploid tumors (both 47%, p < 0.0001). When analyzing the ER- and PR-positive fractions separately in the diploid and aneuploid cell populations of the nondiploid tumors, it became apparent that the ER and PR status in the diploid fraction of the tumor was significantly higher than in the aneuploid fraction (p < 0.0001). For the tetraploid tumors the mean ER- and PR-positive fractions were 79% and 76%, respectively, in the diploid fraction, and this decreased to 45% in the aneuploid cell subpopulation. In the aneuploid tumors this decrease was even more drastic: in the diploid cell population the ER- and PR-positive fractions were 66% and 62%, while this was 38% and 39% in the aneuploid population. These findings illustrate clearly the existence of a heterogeneous distribution of ER/PR expression in breast cancer, related to the loss of a diploid DNA index. Because of its objective quantification of subfractions within the same tumor, MP-FCM can be regarded as a superior method compared to more conventional techniques such as immunohistochemistry and biochemistry.

Flow cytometric DNA and phenotype analysis in pathology. A meeting report of a symposium at the annual conference of the German Society of Pathology, Kiel, Germany, 6-9 June 2000.

This meeting report summarizes the presentations of three different groups that are active in the field of flow cytometry (FCM) in relation to diagnosing and classification of proliferative disorders. The report starts with the contribution from Regensburg about the developments in DNA FCM, the progression to dual parameter determinations, and combination of immunophenotyping in combination with DNA. In the second part, the use of FCM for the detection of isolated tumor cells in the peripheral blood from patients with prostate or breast cancer is discussed in a contribution from Münster. In the third part, from Heerlen, the use of multi-parameter FCM on formalin-fixed paraffin-embedded tissues from solid tumors is discussed as a new development and application in routine surgical pathology.

A novel flow cytometric steroid hormone receptor assay for paraffin-embedded breast carcinomas: an objective quantification of the steroid hormone receptors and direct correlation to ploidy status and proliferative capacity in a single-tube assay.

Semiquantitative estimation of steroid hormone receptors by immunohistochemistry applied to paraffin sections is common practice in surgical pathology. Flow cytometric (FCM) analysis of estrogen receptor (ER) and progesterone receptor (PR) levels provides a faster and more objective quantitative assay. However, a major problem in such FCM analyses of solid tumor samples is the admixture of tumor cells with normal epithelial, stromal, and inflammatory cells. The aim of the underlying study was to investigate the applicability of a recently developed multiparameter flow cytometric methodology for the accurate estimation of the fraction of steroid hormone receptor-positive tumor cells and to explore whether this multiparameter approach allows the detection of specific, clinically relevant subsets of tumors, based on a combination of ploidy level, steroid hormone receptor status, and cell cycle characteristics. For this purpose, samples of 42 breast cancer patients, from which routine immunohistochemistry for ER and PR also was available, were analyzed. From each case, a cell suspension was prepared from the paraffin block by applying a heating and short pepsin digestion step to 50-microm-thick sections. These cell suspensions were double-immunostained for cytokeratin to identify the epithelial cells, and ER or PR, whereas DNA was quantitatively stained with propidium iodide using an optimized protocol. In the entire group of breast tumors, the percentages of ER- and PR-positive cells were registered in the epithelial subfraction, in combination with DNA ploidy and S phase fraction (SPF). A significant correlation was found between the fraction of hormone receptor-positive cells as found by the immunohistochemical and FCM procedures. For ER, a correlation coefficient of r = .87 was found, and for PR r = .62, both P < .0001. It became clear that all the diploid breast tumors had more than 30% tumor cells positive for ER with a SPF lower than 10%, whereas aneuploid tumors contained on average a smaller percentage of steroid hormone receptor-positive cells, and simultaneously an SPF greater than 10%. Our results show that this multiparameter FCM analysis allows an objective and reproducible quantification of the fraction of steroid hormone receptor-positive cells in the relevant epithelial cell compartment in relation to DNA ploidy status and proliferative capacity in a single-tube assay.

Clonality assessment of lymphoproliferative disorders by multiparameter flow cytometry of paraffin-embedded tissue: an additional diagnostic tool in surgical pathology.

A major drawback of immunohistochemical detection of monoclonality in B-cell lymphoproliferative disorders is the lack of contrast between surface-immunoglobulin staining and extracellular immunoglobulin staining. To bypass this drawback, immunophenotyping of single-cell suspensions by flow cytometry is commonly used. Although the expression of immunoglobulin light chain subtype can be quantified rapidly and reliably, the technique is hampered by the requirement of fresh unfixed material. We applied a recently developed technique for the isolation of single cells from formalin-fixed, paraffin-embedded material to measure clonality in B-cell lymphoproliferative disorders (lymphoid tissue (n = 10) and non-Hodgkin's B-cell lymphoma (n = 10). Immunocytochemistry indicated that common cell surface markers as well as the immunoglobulin light chains could be detected in the cell suspensions derived from archival material. In addition, the technique also allowed combined high-resolution DNA flow cytometric analysis. To investigate the effect of formalin fixation on cross-linking of extracellular immunoglobulins to lymphocytes, a double-immunostaining experiment for both light chain immunoglobulins (kappa and lambda) was performed. This experiment showed that this cross-linking was minimal (less than 2%). All cases of reactive lymphoid hyperplasia were DNA diploid and showed a polyclonal expression of immunoglobulin light chains. In contrast, in 9 of 10 non-Hodgkin's B-cell lymphomas, monoclonality was established on the basis of light chain expression, whereas only 6 of 9 cases were conclusive by immunohistochemistry. Four of the 9 cases were DNA aneuploid. One case did not show light chain expression at all by both techniques. However, this case could be classified as malignant by flow cytometric analysis because of the DNA-aneuploid nature of the B-cell subpopulation. The average S-phase fraction (SPF) of the B cells in the reactive lymphoid tissues was 3.5%. The mean SPF values for B cells in DNA-diploid cases of lymphomas was 3.0%, whereas the mean SPF of B cells in DNA-aneuploid cases was 6.1%. The presented technique is superior to immunohistochemistry for the detection of monoclonality in B-cell lymphoproliferative disorders and therefore provides a powerful tool to support the diagnosis of malignant lymphoma in routinely processed archival samples of lymphoid tissues.

The patterns of expression of an apoptosis-related CK18 neoepitope, the bcl-2 proto-oncogene, and the Ki67 proliferation marker in normal, hyperplastic, and malignant endometrium.

Expression of a neoepitope on cytokeratin 18, recognized by the monoclonal antibody M30, is an early indicator of apoptosis in epithelial cells. The aim of this study was to determine the equilibrium between apoptosis (M30), anti-apoptosis (bcl-2), and proliferation (Ki-67) in different endometrial conditions. Paraffin-embedded samples (n = 107), representing proliferative endometrium (18), secretory endometrium (19), postmenopausal endometrium (15), disordered proliferative endometrium (6), simple hyperplasia (12), complex hyperplasia (8), and endometrial adenocarcinoma (29), were evaluated immunohistochemically. The indirect streptavidin-biotin-horseradish peroxidase technique, with 3-amino-9-ethylcarbazole as the chromogen, was used to visualize the reactions. Proliferative endometrium showed high bcl-2 and Ki-67 expression levels with no M30. In the secretory phase, the balance was tipped in favor of M30 with a decrease of bcl-2 and Ki-67. Postmenopausal endometrium revealed high Ki-67 and bcl-2 expression levels and no M30. In complex hyperplasia, M30, bcl-2, and Ki-67 showed increased expression. In endometrial carcinoma, an increasing reactivity for M30 and Ki-67 was seen as the grade progressed. bcl-2 reacted weakly and only in grade 1 cancer. Immunohistochemistry facilitates the study of the expression of proteins related to cyclic endometrial activity. Interruption of these cyclic events is associated with specific disturbances in the expression patterns of these proteins.

Evaluation of the membrane attack complex of complement for the detection of a recent myocardial infarction in man.

The diagnosis of an acute myocardial infarction (MI) can be cumbersome for pathologists. Even with a positive nitroblue tetrazolium (NBT) reaction, haematoxylin and eosin (H&E) evaluation of the myocardial tissue can remain inconclusive. Early signs presumed diagnostic for myocardial infarction, such as hypereosinophilia, waviness, and contraction band necrosis, have to be considered non-specific and are probably reversible signs of ischaemia. Several studies implicate the complement system, and especially complement factor C9, as part of the membrane attack factor (MAC), in cardiomyocyte damage during MI. In a post-mortem study on well-documented cardiological autopsies, we evaluated the use of complement factor C9 immunostaining as a marker for the detection of very recent MI. Forty-three tissue samples from 40 patients were obtained from the left ventricular free wall only, a region that can be specifically attributed to one corresponding coronary artery. As some patients presented with MIs of various stages in that perfusion area, in total 57 observations were possible. C9 immunostaining specifically detected irreversibly damaged (=infarcted) cardiomyocytes, as is implied by the lytic activity of C9/MAC binding to cell membranes. Most interesting was the group of clinically suspected, NBT-positive MIs resulting from very recent myocardial ischaemia. In this population, where H&E evaluation by (cardio-) experienced pathologists was not conclusive, C9 immunostaining clearly pointed towards myocardial infarction in 47% of the cases. In conclusion, C9 immunostaining, routinely practicable in the pathology laboratory, has an additional value in discriminating between reversible ischaemia and infarcted cardiomyocytes in very early MIs.

Apoptosis, bcl-2 expression, and proliferation in benign and malignant endometrial epithelium: An approach using multiparameter flow cytometry.

OBJECTIVE: Disturbances in the regulation of cell proliferation and differentiation play an important role in the formation of neoplastic lesions. Consequently, abnormalities in apoptosis regulation may contribute to this process. Expression of a neoepitope on cytokeratin 18, unmasked by an early caspase cleavage event and recognized by the novel monoclonal antibody M30, is an indicator of early epithelial cell apoptosis. The purpose of this study was to evaluate the quantitative relation among apoptosis (M30), cell persistence (bcl-2), and proliferation (S-phase fraction; SPF) in malignant and benign endometrium. METHODS: Using multiparameter DNA flow cytometry on 54 formalin-fixed paraffin-embedded samples from benign (proliferative, secretory, inactive, and hyperplastic endometrium) and malignant (grades 1-3 endometrial adenocarcinoma) endometrial tissue, bcl-2 expression and M30 reactivity were assessed together with the SPF in the cytokeratin-positive epithelial cells. RESULTS: Benign cyclic endometrium showed a relatively high bcl-2 expression and low M30 reactivity in the proliferative phase whereas in the secretory phase this relation was inverse. In endometrial hyperplasia the expression of bcl-2 was increased compared to that in secretory and postmenopausal endometrium, but still below the level of proliferative samples. The expression of M30 also increased compared to normal proliferative endometrium but did not reach the level of endometrium in the secretory phase of the menstrual cycle. In cancer the expression of bcl-2 decreased with the progression of differentiation grade. For M30 expression this relation was inverse. Overall there was a significant increase of M30 reactivity in cancerous compared to hyperplasia and normal cyclic endometrium. CONCLUSION: Transition of endometrial epithelium from hyperplasia to cancer seems to involve both increased apoptosis and decreased bcl-2 expression. Flow cytometric evaluation of M30 and bcl-2 expression levels, with the SPF, in currettage specimens from postmenopausal patients complaining of bleeding provides a quantitative assessment of endometrial apoptosis, anti-apoptosis, and proliferation. Further studies are needed to determine the relationship among these three processes as indicators of the biological behavior of gynecological tumors.

Immunocytochemical detection and mapping of a cytokeratin 18 neo-epitope exposed during early apoptosis.

A neo-epitope in cytokeratin 18 (CK18) that becomes available at an early caspase cleavage event during apoptosis and is not detectable in vital epithelial cells is characterized. The monoclonal antibody M30, specific for this site, can be utilized specifically to recognize apoptotic cells, which show cytoplasmic cytokeratin filaments and aggregates after immunohistochemistry with M30, while viable and necrotic cells are negative. The number of cells recognized by the antibody increases after induction of apoptosis in exponentially growing epithelial cell lines and immunoreactivity is independent of the phosphorylation state of the cytokeratins. The generation of the M30 neo-epitope occurs early in the apoptotic cascade, before annexin V reactivity or positive DNA nick end labelling. In a flow cytometric assay, the majority of the M30-positive cells appear in the 'apoptotic' subG1 peak. Tests with synthetic peptides define positions 387-396 of CK18, with a liberated C-terminus at the caspase cleavage site DALD-S, as the ten-residue epitope of M30. This epitope starts at the end of coil 2 of the predicted CK18 structure, at a probable hinge region, compatible with the sensitivity to proteolytic cleavage. The definition of a specific caspase cleavage site in CK18 as a neo-epitope can be used for quantification of apoptotic epithelial cells with immunocytochemical techniques and is applicable to both fresh and formalin-fixed material.

Heat pretreatment increases resolution in DNA flow cytometry of paraffin-embedded tumor tissue.

BACKGROUND: Flow cytometry of single-cell suspensions prepared by enzymatic digestion from formalin-fixed, paraffin-embedded tissue suffers from several major drawbacks. The most important factors that influence the results are the high and unpredictable coefficients of variation (CVs) of the G0/G1 peak in the DNA histogram and reduction of propidium iodide (PI) intercalation with DNA, resulting from protein cross-linking by formalin. METHODS: In this study we introduce a heating step (2 h incubation in citrate solution at 80 degrees C) prior to a brief pepsin digestion of tissue sections in the protocol for DNA content analysis of formalin-fixed and paraffin-embedded tissue. This new method is compared with established methods for the preparation of cell suspensions from frozen and paraffin-embedded tissues with respect to cell yield, DNA histogram resolution, DNA dye saturation kinetics, cell cycle parameters, and antigen retrieval in various epithelial and nonepithelial tissues. RESULTS: The recovery of single cells from the paraffin sections was doubled by the heat treatment step, while the limited time of proteolysis resulted in decreased cell debris. Furthermore, an increased fraction of cells became cytokeratin-positive, while these immunocytochemically stained cells also exhibited a higher mean fluorescence intensity. The DNA histograms prepared from cell suspensions obtained according to this new protocol showed a significantly improved resolution, leading to a better identification of peridiploid cell populations. Heat pretreatment of paraffin-embedded archival tissue sections showed PI saturation kinetics similar to, or even better than, those of fresh unfixed tissues, independent of duration of fixation. CONCLUSIONS: This new method, making use of routinely available antigen retrieval principles, thus allows high-resolution DNA analysis of routinely fixed and paraffin-embedded tissue samples. Using external reference cells, inter- and intralaboratory standardization of DNA histograms can be achieved.

Reduced E-cadherin expression is associated with increased lymph node metastasis and unfavorable prognosis in non-small cell lung cancer.

E-cadherin is a calcium-dependent, epithelial cell adhesion molecule whose reduced expression has been associated with tumor dedifferentiation and increased lymph node metastasis in clinical studies involving several carcinomas. In this study, 111 patients who had previously undergone complete resection and systematic mediastinal lymph node dissection for non-small cell lung cancer (NSCLC) were studied retrospectively. In the primary tumor, as well as in the lymph node metastases, E-cadherin expression was detected by immunohistochemistry using a monoclonal antibody (HECD-1; Takara, Otsu, Japan). There was a significant inverse correlation between E-cadherin expression and lymph node stage (Pearson correlation coefficient -0.52, p = 0.0001) as well as tumor differentiation (Pearson correlation coefficient -0.27, p = 0.005). Moreover, Kaplan and Meier survival estimates showed a significant correlation between E-cadherin expression and patient survival in log rank testing (p = 0.006). In the patient group with the highest proportion of E-cadherin positive tumor cells, 60% of the patients were still estimated to be alive at 36 mo, versus 32% of the patients in the group classified as showing negative E-cadherin expression. Our findings provide clinical evidence that reduced E-cadherin expression is associated with tumor dedifferentiation, increased lymphogenous metastasis and poor survival. It seems therefore that E-cadherin expression might be an important prognostic factor in NSCLC.

E-cadherin and calretinin: a useful combination of immunochemical markers for differentiation between mesothelioma and metastatic adenocarcinoma.

AIMS: To assess the diagnostic accuracy of combinations of antibodies in the differential diagnosis of metastatic carcinomas and mesotheliomas in pleural lesions. METHODS AND RESULTS: The specificity and sensitivity of the commercially available antibodies Ber-EP4, MOC-31, CEA, B72.3, CD15, E-cadherin and calretinin were evaluated using an indirect immunoperoxidase staining technique. This technique was applied to formalin-fixed, paraffin-embedded tissue blocks of pleural lesions. Twenty-one patients with metastatic carcinoma (MC) and 20 patients with malignant mesothelioma (MM) were included. The combination E-cadherin/calretinin had the highest specificity (MC 100% and MM 91%) and sensitivity (MM 100% and MC 91%) considering both categories of tumours. CONCLUSIONS: The combination of E-cadherin/calretinin appears to be a suitable panel for distinguishing metastatic carcinomas and mesotheliomas in pleural lesions. The additional value of other markers is limited.