Immunocytochemistry in effusion cytology

Simple and rapid flow cytometry assay for the detection of malignant epithelial cells in body fluids

INTRODUCTION

Morphology is routinely used for detecting malignant cells in body fluids, but it has limitations. Recently, flow cytometry (FCM) is used as an effective tool for studying non-haematological malignancies. The main objective of this study is to standardize a simple and rapid FCM test for the detection of malignant epithelial cells in body fluids.

MATERIALS AND METHODS

Body fluids that had been processed for cytology/cytology and FCM were enrolled in this prospective study. We developed a fluorescent-labelled, monoclonal antibody panel composed of cell surface markers for this FCM assay. We compared the results of cytology/cell block and FCM.

RESULTS

A total of 121 fluid samples were studied. Comparing the diagnostic performance of cytology/cell block and FCM, 52 (43%) cases were positive and 60 (49.5%) cases were negative for carcinoma cells by both techniques. Nine cases showed discordant results between the two techniques. Six cases were cytology+ but FCM- and three cases were FCM+ cytology-. Clustered Epithelial Cell Adhesion Molecule (EpCAM)-positive events with high scatter properties were definitive for positive diagnosis by FCM. We studied PD-L1 expression in 13 cases by FCM. Six cases were reported as false negative by this FCM assay due to hypocellularity and lack of EpCAM expression in malignant cells.

CONCLUSIONS

This FCM assay is simple, easier and cost-effective yielding sensitive results with no inter-observer variability. FCM would become a valuable tool to complement routine diagnostic cytology and reduces misdiagnosis.

Diagnostic analysis of pleural fluid cell blocks using relevant immunohistochemical markers in clinically suspicious cases of malignancy

Objective

Thoracocentesis is a less invasive and expensive procedure than pleural biopsy, enabling sample collection for cytological evaluation. Cell blocks prepared from these samples provide histopathological diagnoses; further, immunohistochemistry (IHC) can be performed for subtyping malignancies, guiding the clinician in choosing the appropriate treatment modality for the patient. We aimed to determine the various histological subtypes of malignancies using cell block IHC and compare the cell block and conventional cytology methods for diagnosing malignant pleural effusion.

Material and Methods

All pleural fluid samples from the clinically suspicious cases of malignancy collected at the Department of Pathology, Government Medical College Kottayam, India, during 18 months, except duplicate and inadequate samples, were included in this prospective observational study. IHC was performed on cell blocks that were positive for malignancy.

Results

This study analyzed 630 samples, of which 121 cell blocks demonstrated the presence of malignancy. Overall, 80%, 13%, and 7% of cases were negative, suspicious, and positive for malignancy based on conventional cytology, and 81%, 0%, and 19% were negative, suspicious, and positive for malignancy based on cell blocks, respectively. Among all malignancies, adenocarcinomas from the lung (56%) were the most common, followed by adenocarcinomas from the breast (6%), squamous cell carcinomas (5%), and adenocarcinomas from the ovary (3%). Cell blocks helped detect more malignancies (19%) than conventional cytology (7%), despite a moderate agreement between both methods.

Conclusion

Adenocarcinomas were the most common cause of malignant pleural effusions, and the most frequent site of origin was the lungs. Cell blocks helped diagnose more malignancies than conventional cytology.

Visualizing neutrophil extracellular traps in septic equine synovial and peritoneal fluid samples using immunofluorescence microscopy

Septic synovitis and peritonitis are routinely diagnosed in horses based on clinical examination findings and laboratory assessment of synoviocentesis and abdominocentesis samples, respectively. Diagnosis is difficult in some cases because of an overlap in laboratory results for septic and non-septic inflammation. Neutrophil extracellular trap (NET) formation is part of the innate immune response against pathogens. Identifying and quantifying NETs, which have not been explored in clinical samples from horses with septic synovitis and peritonitis, to our knowledge, may be helpful in detecting infectious processes. Our main objective was to determine whether NETs could be visualized in septic equine synovial and peritoneal fluid cytology samples using immunofluorescence with antibodies against citrullinated histone H3 (Cit-H3) and myeloperoxidase (MPO). We analyzed 9 synovial and 4 peritoneal fluid samples. NET percentages were quantified using a simple counting technique, which is suitable for high-quality, well-preserved, and stained cytospin smears. NETs were evident in all septic samples and were absent in a non-septic sample; NETs were better visualized with Cit-H3 than with MPO immunolabeling. Overall, we believe that there is the potential for NETs and associated markers to be used to investigate and understand septic inflammation in horses.

Cytomorphology and immunocytochemical features of ovarian granulosa cell tumors in ascites or peritoneal washings: A retrospective review

AIM

To summarize the cytomorphology and immunocytochemistry features of OGCT in ascites or peritoneal washings.

METHODS

All cases of histology sections, cytology smears, cell block slides and immunohistochemical staining were reviewed. A panel of immunohistochemistry antibodies consisting of Inhibin, Calretinin, BerEP4 and MC was performed for diagnosis and differential diagnosis.

RESULTS

Seven positive cases (21.2%) in ascites and peritoneal washings were identified in 33 patients with OGCT, which is higher than early studies with positive rate of 7.4%. Clinicopathologic features including tumor size and the incidence of endometrial atypical hyperplasia or carcinoma (EAH/EC) displayed no statistical difference between groups with positive and negative cytology. Immunocytochemical results usually showed typical staining pattern with α-inhibin, calretinin positive and BerEP4, MC negative. Features of granulosa cells, including nuclear hyperplasia and overlapping, can be observed in all seven positive cases. Nuclear grooves or small conspicuous nucleoli were occasionally observed in the smear. However, features of cell clusters mimicking Call-Exner bodies, cytoplasmic vacuoles or single cell necrosis were not found on smear. Call-Exner bodies and mitosis can only be found on cell blocks. All cases of follow-up information were available and three cases displayed progression and there was a statistical difference between groups with positive and negative cytology.

CONCLUSION

OGCT with positive cytology in ascites and peritoneal washings tend to have a larger tumor size and higher rates of disease progression. A panel of complementary biomarkers can greatly increase the detection rate and help in differential diagnosis in ascites or peritoneal washings of OGCT.

Immunocytochemistry of effusion fluids: Introduction to SCIP approach

Due to the remarkably wide morphologic spectrum of reactive mesothelial cells, some of the effusion fluids may be difficult to interpret with objective certainty by cytomorphology alone. Cytomorphology of well to moderately differentiated adenocarcinomas (responsible for the bulk of malignant effusions) may overlap with floridly reactive mesothelial cells. Even mesotheliomas including diffuse malignant epithelioid mesothelioma, are usually cytomorphologically bland without unequivocal features of malignancy. The intensity of challenge depends on the interpreter's training or experience level, institutional demographics of patients (such as type of prevalent diseases, predominant sex and age group), technical support, and quality of cytopreparatory processing. In general immunocytochemistry is valuable adjunct to facilitate objective interpretation with or without other ancillary techniques as indicated. An increasing number of immunomarkers is further refining the contribution of immunohistochemistry to this field. However, application of immunohistochemistry to effusion fluids is relatively challenging because of many variables. Multiple factors such as delay after specimen collection, specimen processing related factors including fixation and storage; ambient conditions under which paraffin blocks are archived (for retrospective testing); antigen retrieval method; duration of antigen retrieval step; antibody clone and dilution; and antibody application time are identical to application of immunohistochemistry in other areas. The significant challenge related to the potential compromization of the immunoreactivity pattern due to exposure to non-formalin fixatives / reagents is also applicable to effusion fluid specimens. The immunoreactivity results would be compared and corelated with cumulative metadata based on the reported studies performed and validated on formalin-fixed paraffin-embedded tissue sections. Deviating from such protocols may lead to suboptimal results, which is not uncommon in clinical practice with potential compromization of patient care and related liability. Because of this, it is critical to perform immunocytochemistry on formalin-fixed cell-block sections only. In addition, unless the interpretation criteria for immunohistochemical evaluation of effusion fluids are not modified specifically, it may not be productive in resolving some challenging cases. However, this aspect is not well elaborated in the literature. A basic and critical challenge is finding and locating the cells of interest in cell-block sections of effusion fluids. A unique approach is to choose a fundamental immunopanel which highlight the mesothelial and inflammatory cells in reactive effusion fluids to create the basic map. This allows detection of a 'second-foreign' population which can be immunocharacterized further with the help of subtractive coordinate immunoreactivity pattern (SCIP) approach elaborated here.

Radiation-associated Angiosarcoma Presenting as Massive Pleural Effusion

A 67-year-old man was admitted to our hospital for massive pleural effusion. He had a history of mandibular gingival carcinoma treated with radiation therapy (RT). Based on the cytology findings of pleural effusion and a thoracoscopic pleural biopsy, we finally diagnosed him with radiation-associated angiosarcoma. Retrospective cell-block immunocytochemistry with pleural effusion also showed potential utility for the diagnosis. This case highlights the importance of considering the possibility of radiation-associated secondary cancer in patients with pleural effusion who have a history of RT.

Evaluation of DNA/RNA quality from cell block of malignant mesothelioma and lung adenocarcinoma

Malignant mesothelioma (MM) is a rare and highly lethal tumor that arises from mesothelial tissue on the surface of the chest and abdominal cavity. Cytological examination of body fluids, including pleural fluid and ascites, is essential for the differentiation of malignant mesothelioma from other carcinomas, such as lung and gastrointestinal carcinomas and metastatic tumors. To evaluate the effectiveness of cell block preparation procedures, which are used for immunocytochemical staining and genetic panel analysis of tumor-specific gene mutations, we used various fixatives. We also evaluated the effects of immunostaining, and the quality of nucleic acids for genetic analysis.

METHODS

Cell blocks were prepared using the malignant mesothelioma cell lines MESO4 and H226 and non-small cell lung carcinoma cell line HCC78. The cells were fixed using 10% neutral buffered formalin and four different fixatives for liquid cytology. Fixed cells were formed into cell clusters using sodium alginate or centrifugation, and paraffin-embedded cell blocks were prepared.

RESULTS

Cell blocks were morphologically evaluated by hematoxylin and eosin and immunocytological staining, and the nucleic acid quality was evaluated by DNA/RNA extraction, qPCR, and next-generation sequence analysis. D2-40 and WT1 staining differed depending on the fixation solution and the cell cluster formation method; however, the degree of nucleic acid degradation was not impaired by any method.

CONCLUSION

Although the morphological evaluation of cytology specimens is affected by the method of cell block preparation, it is still useful for nucleic acid extraction and gene panel analysis, as long as there are sufficient amounts of tumor cells.

Serous fluids and hematolymphoid disorders

Diagnosing hematolymphoid neoplasm by evaluating fine-needle aspiration (FNA) cytology sample is controversial and requires experience and clinical skills. This concept becomes more challenging when evaluating hematolymphoid neoplasm in body fluid. Differentiating between low-grade lymphoma and reactive lymphocytes is often difficult by morphology alone as reactive lymphoid cells may acquire activation morphology from being exposed to different cytokines within the body fluid. However, in most cases there are specific features that may aid in differentiating small reactive from non-reactive lymphocytes including the round shape of the nucleus, the absence of visible nucleoli and the presence of fine clumped chromatin. In large cell lymphoma and leukemia cells involvement of body fluid this concept becomes less challenging. Large cell lymphoma and leukemia cells tend to have large size nuclei, less mature chromatin, and visible nucleoli with and without cytoplasmic vacuoles. However, to reach accurate diagnosis and subclassification, the utilizing of flow cytometry, to confirm monoclonality, and other ancillary studies such immunocytochemistry, cytogenetics and molecular studies is needed. This review article will be incorporated finally as one of the chapters in CMAS (CytoJournal Monograph/Atlas Series) #2. It is modified slightly from the chapter by the initial authors in the first edition of Diagnostic Cytopathology of Serous Fluids.

Immunocytochemistry of effusions: Processing and commonly used immunomarkers

Definitive cytopathological interpretation of some of the effusion fluids may not be possible based on cytomorphological evaluation alone. As discussed in other reviews, this is due to various reasons specifically applicable to effusion fluids including remarkably wide morphologic spectrum of reactive mesothelial cells overlapping with some well to moderately differentiated metastatic carcinoma. The challenge is subject to various factors including level of interpreter training or experience, institutional demographics (such as type of prevalent diseases, predominant sex and age group), technical advances in ancillary support, and expertise in cytopreparatory processing. In such cases immunohistochemistry performed on cell-block sections is simple objective adjunct with or without other ancillary techniques. Ongoing increase in number of immunomarkers along with rabbit monoclonal antibodies with relatively higher affinity is further refining this field. SCIP (subtractive coordinate immunoreactivity pattern) approach, discussed as separate dedicated review article, facilitates refined interpretation of immunoreactivity pattern in coordinate manner on various serial sections of cell-blocks. However, many variables such as delay after specimen collection, specimen processing related factors including fixation and storage; ambient conditions under which paraffin blocks are archived (for retrospective testing); antigen retrieval method; duration of antigen retrieval step; antibody clone and dilution; and antibody application time are common with application of immunohistochemistry in other areas. This review is dedicated to highlight technical aspects including processing of effusion specimens for optimum immunocytochemical evaluation along with commonly used immunomarkers in effusion cytopathology. This review focuses on the technical and general information about various immunomarkers.

Application of multicolour flow cytometry in the detection of metastatic carcinoma in serous effusions: Special emphasis in atypical cytology

INTRODUCTION

We evaluated the role of simultaneous use of multiple antibodies in flow cytometry (FCM) to detect metastatic carcinomas in effusion samples.

METHODS

Cytological examination of 75 successive cases of effusion samples was performed. There were 48 peritoneal, 26 pleural and one pericardial fluid. Multi-coloured FCM examination was undertaken using a cocktail of CD45, CD14 and epithelial cell adhesion molecule (EpCAM), antibodies tagged with different fluorochromes. The percentage of EpCAM positivity was calculated in the CD45 and CD14 dual negative population by selective gating. The EpCAM value was correlated with the cytological findings, follow-up data and MOC-31 immunostaining.

RESULTS

There were 20 benign, 35 malignant and 20 atypical cases diagnosed on cytomorphology. The primary sources of carcinomas were mainly from the ovary, followed by lung, gall bladder, intestine and other areas. Out of 20 cytologically benign cases, there were two malignant cases on the final follow-up, and EpCAM on FCM picked up all 18 benign cases and one malignant case. Out of 35 cytologically detected malignant cases, EpCAM picked up 32 malignant cases. The EpCAM detected 15/18 malignant and both benign cases out of 20 cytological atypical cases. EpCAM antibody by FCM showed 87% sensitivity, 100% specificity, 100% positive predictive value and 74% negative predictive value.

CONCLUSION

This comprehensive study highlights the potential use of multi-coloured FCM along with cytological examination to diagnose metastatic carcinoma in effusion samples. Multi-coloured FCM is rapid and quantitative and is helpful in atypical cases.

"Single-cell pattern" of adenocarcinoma cells in effusion cytology: Morphologic challenges of lung cancer

BACKGROUND

Lung adenocarcinomas present as tight clusters and three-dimensional balls in effusion specimens. Unlike carcinomas of breast and stomach where singly lying malignant cells are seen in effusion samples, lung adenocarcinomas usually show cohesive morphology. This single-cell pattern may also be confused with reactive mesothelial cells. We studied the frequency of pulmonary adenocarcinoma with single-cell pattern cytomorphology in pleural effusion specimens.

MATERIALS AND METHODS

All cases reported as either suspicious or positive for malignancy on pleural effusion cytology (PFC) over the past 1 year were retrieved. The clinical details were obtained from requisition forms. Cases with predominant single-cell pattern, clinically suspicious of carcinoma lung were segregated. These were de-stained and immunocytochemistry (ICC) for TTF-1 was performed.

RESULTS

Of 103 cases reported as either suspicious or positive for malignancy on PFC, 29 had a predominant single-cell pattern. Of these, 13 (44.8%) were primary lung carcinoma. The rest were metastasis from ovary (5; 17.2%), breast (2; 6.9%), stomach (2; 6.9%), lymphoma (1; 3.5%), and Ewing's sarcoma (1; 3.5%). Five (17.2%) were those with unknown primary. All cases of lung carcinoma were positive for TTF-1 ICC.

CONCLUSION

Single-cell pattern of pulmonary adenocarcinoma is commoner than popularly believed. This pattern may be difficult to differentiate from carcinoma cells of other sites as well as from reactive mesothelial cells. A high degree of suspicion is therefore needed to perform relevant ICC to clinch the correct diagnosis.

[Mass spectrometry-applications in pathology]

BACKGROUND

Currently, more complex and extensive diagnostic pathology work-up of sometimes only limited sample material is necessary to ensure optimal patient treatment. This often includes genomic analyses. However, dynamic changes within an organism or tumor can be better reflected at the protein level. Therefore, proteomic technologies would seem to be the solution.

OBJECTIVES

To evaluate the application of different proteomic techniques to analyze body fluids and tissue samples with regards to implementation in diagnostics.

MATERIALS AND METHODS

All studies utilized mass spectrometry-based methods in order to achieve differentiation of a number of different patient groups in various diseases.

RESULTS

Whereas classical proteomic methods are particularly suitable for analyzing serum samples in order to diagnose bladder cancer or chronic hepatitis C, tissue analyses would require prior tissue lyses, thus erasing possible information to be obtained from histology. Imaging mass spectrometry offers a solution as it allows for the analysis of an intact tissue section. Possible applications and the added benefit of this method could be shown using various examples of tumors (prostate cancer, Hodgkin's lymphoma, cervical cancer, and different types of adenocarcinomas).

CONCLUSIONS

Mass spectrometry-based technologies allow diagnostic confirmation with high sensitivity and specificity. In comparison to routine diagnostic approaches, results can be achieved faster, using less sample material, and with comparable accuracy.

Diagnostic Value of the EZH2 Immunomarker in Malignant Effusion Cytology

BACKGROUND

Differentiating reactive mesothelial cells from metastatic carcinoma in effusion cytology is a challenging task. The application of at least 4 monoclonal antibodies including 2 epithelial markers (Ber-EP4, MOC-31, CEA, or B72.3) and 2 mesothelial markers (calretinin, WT-1, CK5/6, or HBME-1) are often useful in this distinction; however, it is not readily available in many resource-limited developing countries. Aberrant immunoexpression of enhancer of zeste homolog 2 (EZH2), a transcriptional repressor involved in cancer progression, is observed widely in various malignancy. In this study, we evaluate the diagnostic value of EZH2 as a single reliable immunomarker for malignancy in effusion samples.

METHODS

A total of 108 pleural, peritoneal, and pericardial effusions/washings diagnosed as unequivocally reactive (n = 41) and metastatic carcinoma (n = 67) by cytomorphology over 18 months were reviewed. Among the metastatic carcinoma cases, 54 were adenocarcinoma and others were squamous cell carcinoma (n = 1), carcinosarcoma (n = 1), and carcinoma of undefined histological subtypes (n = 11). Cell block sections were immunostained by EZH2 (Cell Marque, USA). The percentages of EZH2-immunolabeled cells over the total cells of interest were calculated. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off score to define EZH2 immunopositivity.

RESULTS

A threshold of 8% EZH2-immunolabeled cells allows distinction between malignant and reactive mesothelial cells, with 95.5% sensitivity, 100% specificity, 100% positive predictive value, and 93.2% negative predictive value (p < 0.0001). The area under the curve was 0.988.

CONCLUSION

EZH2 is a promising diagnostic biomarker for malignancy in effusion cytology which is inexpensive yet trustworthy and could potentially be used routinely in countries under considerable economic constraints.

Role of Ancillary Techniques in Fluid Cytology

The cytologic evaluation of serous effusions may be challenging for a number of reasons. Distinction of benign, reactive conditions from malignancy represents the main focus when examining these specimens. The morphologic diagnosis of malignancy may be difficult due to the relative paucity of abnormal cells. In other situations, cellularity is not an issue, but the ability to confidently identify a second, foreign (i.e., tumor) population within a background mesothelial cells on the basis of cytomorphologic features alone may pose problems. Cases with definitive morphologic evidence of malignancy may require additional studies in order to determine the tumor subtype and, in the case of carcinoma, the primary site of origin. Cases in which a definitive and precise diagnosis of malignancy is made may be optimal candidates for further molecular testing in order to gain prognostic information and guide personal therapeutic decisions. Finally, while an inflammatory or infectious condition can be suggested on the basis of cellular components and associated background elements, the identification of causative agent(s) may be difficult without additional studies. In all of these situations, the use of ancillary studies and techniques is critical; their utility and appropriate application are the subject of this review.

The cell tube block technique and an immunohistochemistry panel including Wilms tumor 1 to assist in diagnosing cavitary effusions in dogs and cats

BACKGROUND

Cell blocks and immunohistochemistry (IHC) are increasingly recognized as being complementary tools for cytologic diagnostics, especially for neoplastic diseases.

OBJECTIVES

The study aimed to evaluate the utility of cell tube block (CTB) IHC for refining the diagnosis of effusions in dogs and cats.

METHODS

Cavitary effusions (n = 25) from dogs and cats classified by cytology as reactive, neoplastic, borderline (suspicious of neoplasia), and chylous were studied. CTB sections were stained with H&E, and immunostained with PAX-5, CD3, pancytokeratin (CK), vimentin, and Wilms tumor 1 protein (WT1) antibodies, according to the cytologic diagnoses. A histologic case series of confirmed normal, reactive, and neoplastic mesothelium and several different carcinomas were included to test the utility of WT1 as a marker of mesothelial cells.

RESULTS

CTBs had a layered appearance with reduced background staining. CD3 and PAX5 immunolabeling allowed immunophenotype assessment in all of the lymphoma cases. In carcinomatous effusions, neoplastic cells were CK-positive, WT1-negative, and vimentin-negative (except for two cases). Wilms tumor 1 protein was positive in the nuclei of normal, reactive, and neoplastic mesothelial cells, and ovarian carcinomatous cells. Other carcinomas and lymphomas were negative.

CONCLUSIONS

CTBs are valuable tools to assist in making a diagnosis of cavitary effusions in dogs and cats, and WT1 is a promising marker to differentiate mesothelial from carcinomatous cells.

Discerning the Primary Carcinoma in Malignant Peritoneal and Pleural Effusions Using Imaging Mass Spectrometry-A Feasibility Study

PURPOSE

Malignant effusions challenge diagnostic accuracy due to cytomorphologic overlaps between various malignant primaries. Workup of this material to establish a correct diagnosis is time consuming and limited by the sparsity of material. In order to circumvent these drawbacks, the use of MALDI imaging MS (IMS) as a diagnostic platform has been explored.

EXPERIMENTAL DESIGN

Cytology cell blocks from malignant effusions (serous ovarian carcinoma and several non-ovarian carcinomas including gastric adenocarcinoma) containing at least 30% neoplastic cells are selected for generation of cytology microarrays (CMA). CMA sections are transferred to conductive glass slides, subjected to on-tissue tryptic digestion, and matrix application for MALDI-IMS analysis.

RESULTS

Supervised classification analysis identifies serous ovarian carcinomas as the source of malignant effusions with a sensitivity of 85.7% when compared to samples from all other included primary sites. When compared to gastric adenocarcinoma, serous ovarian carcinoma samples can be delineated with a sensitivity of 97.3%.

CONCLUSION AND CLINICAL RELEVANCE

These preliminary results highlight that MALDI-IMS allows subtyping of malignant effusions to identify the precise origin of neoplastic cells. While achieving similar results compared to classical approaches such as immunocytology, more material is conserved that will be available for further tests.

Updates in Effusion Cytology

Effusion cytology plays multiple roles in the management of benign and malignant disease, from primary diagnosis to tissue allocation for ancillary diagnostic studies and biomarker testing of therapeutic targets. This article summarizes recent advances in pleural effusion cytology, with a focus on the practical application of immunohistochemical markers, cytogenetic techniques, flow cytometry, and molecular techniques for the diagnosis and management of primary and secondary neoplasms of the pleura.

[Application of immunocytochemistry as a diagnostic aid: Experience in a tertiary university hospital in Cali, Colombia]

INTRODUCTION

Immunocytochemistry is very useful in the differentiation of benign and malignant lesions, through the use of specific antibodies that differentiate the cells according to their origin. This study aims to describe the application of immunohistochemistry to the cytological study of different sample types at the Valle del Lili Foundation.

MATERIALS AND METHODS

A descriptive, retrospective, observational study was carried out with cytologies registered in the database of the pathology department of the Fundación Valle del Lili, between December 2015 and October 2017.

RESULTS

Fifty-four cytological samples with immunocytochemistry were included. It was possible to perform both the cell block and the liquid-based cytology button to 38.88% (n=21) of the total samples, finding from the results of both types of cytology, a Cohen's Kappa coefficient of 0.80 (95%CI: (0.4-1.0), P<.001. The most commonly used markers were: Calretinin, MOC-31, EMA, TTF1, PAX8, and Calcitonin. Out of the cytological studies positive for malignancy, a definitive diagnosis was made with a biopsy in 58.1% (n=25), with a Cohen's Kappa coefficient of 1.0 (95%CI: 1.0-1.0), P<.001.

DISCUSSION

This study provided data that permits the implementation of liquid-based cytology button for immunocytochemical studies, using assessable markers with agreement with cell-block cytology. Furthermore, it provides data useful for future research in this field.

Performance of the UroVysion® FISH assay for the diagnosis of malignant effusions using two cutoff strategies

The cytological examination of cavity fluids has limited sensitivity in the diagnosis of malignancy. Aneuploidy, which is commonly observed in neoplastic cells, could potentially be used as an ancillary diagnostic tool. To evaluate the detection of aneuploid cells in cavitary effusion samples using the fluorescence in situ hybridization (FISH) assay UroVysion^® with some adaptations and two different cutoff strategies. Seventy samples of pleural or peritoneal fluid with positive (n = 40), negative (n = 15), or suspicious (n = 15) oncotic cytology were subjected to FISH assay with the multitarget UroVysion^® kit, which is composed of probes that hybridize to the centromeric region of chromosomes 3, 7, and 17 and to the locus 9p21. FISH performance was evaluated using two different cutoffs: (1) the manufacturer's cutoff (M‐FISH) and 2) a proposed cutoff (P‐FISH). Using M‐FISH, the diagnostic sensitivity was 57.1%, specificity 87.5%, and accuracy 60.0%; with P‐FISH, the sensitivity was 87.3%, specificity 71.4%, and accuracy 85.7%. When combined with cytology, the sensitivity, specificity, and accuracy were 88.0%, 83.3%, and 87.8%, respectively. Malignant cells presented a predominance of chromosomal gains. The UroVysion^® test using the P‐FISH cutoff was effective in demonstrating aneuploid cells in all malignant effusions, confirming the diagnosis of malignancy even in cases with suspicious cytology.

Tyrosinase mRNA RT-PCR Analysis as an Additional Diagnostic Tool for the Identification of Melanoma Cells in Biological Fluid Samples other than Blood: A Preliminary Report

Reverse transcription polymerase chain reaction (RT-PCR) of tyrosinase mRNA has been applied for the detection of melanoma cells in the peripheral blood, lymph nodes and bone marrow of melanoma patients. We evaluated the diagnostic accuracy of RT-PCR in comparison to standard cytology and immunocytochemistry (ICC) for the identification of melanoma cells in biological fluids other than blood. Tyrosinase expression was evaluated together with standard cytology and ICC (anti-S100, HMB-45 and Melan-A antibodies) in biological fluid samples collected from 17 melanoma patients according to the site of metastatic involvement or clinical suspicion (eight cerebrospinal fluid (CSF) samples; three pleural effusions; four ascites; one bile sample, one pericardial effusion); 17 samples collected from patients with non-melanoma metastatic cancer were used as controls. Tyrosinase expression in the biological fluid sample was compared with the expression determined at the same time in peripheral blood. Positive tyrosinase expression was found in 12/17 melanoma and 3/17 non-melanoma cancer patients. Cytology/ICC showed the presence of neoplastic cells in only 7/12 melanoma samples with positive tyrosinase expression: radiological evidence of disease involvement was found in all these patients (three meningeal, two pleural, two peritoneal). Clear-cut radiological evidence of disease involvement at the sampling site was found in the five patients with negative cytology/ICC and positive RT-PCR (one CSF; four serous membrane effusions); all patients died of disease progression within four months of sampling. The five patients who were negative for both cytology/ICC and RT-PCR did not show any clinical evidence of disease recurrence at the sampling site. Only five of the 12 metastatic patients with positive tyrosinase expression in biological fluid showed positivity for tyrosinase in the peripheral blood. These preliminary results suggest that the analysis of biological fluids other than blood could be considered as a new potential clinical field of application for the tyrosinase mRNA assay.

Improving the cytological diagnosis of high-grade serous carcinoma in ascites with a panel of complementary biomarkers in cell blocks

INTRODUCTION

Precise cytological diagnosis of pelvic high-grade serous carcinoma (HGSC) in ascites is important for tumour staging, therapeutic decision-making and prognostic evaluation. However, it can often be difficult to distinguish metastatic HGSC cells from reactive mesothelial cells based on morphology alone. Immunocytochemical analysis of ascites cell blocks has been used to obtain accurate diagnosis and provide a reliable basis for treatment decisions in the clinic. This study was performed to determine whether a panel of antibodies is necessary to achieve high specificity and sensitivity for the identification of HGSC cells.

METHODS

Ascites samples from 70 cases (70/253, 27.7%) of histologically confirmed HGSC were postoperatively collected from 2012 to 2015 and were immunocytochemically analysed.

RESULTS

The sensitivity and specificity of Ber-EP4 (a marker of HGSC) for detecting HGSC was 85.7% and 82.1%, respectively, whereas the sensitivity and specificity of HBME-1 for identifying mesothelial cells was 100% and 68.3%, respectively. To improve the rate of detection further of HGSC, 29 cases of ascites were also stained for E-cadherin (a marker of HGSC) and calretinin (a marker of mesothelial cells). The combination of Ber-EP4 and E-cadherin as markers of adenocarcinoma cells increased the sensitivity and specificity for HGSC detection to 100% and 88.9%, respectively. Meanwhile, the sensitivity and specificity for mesothelial cell identification increased to 100% and 90%, respectively, when HBME-1 and calretinin were combined.

CONCLUSION

This panel of complementary biomarkers is valuable and ideal for the differential diagnosis of HGSC based on ascites cytology.

Trends in Pleural Effusion Research

Background:

Research in pleural diseases has traditionally been neglected but is now growing.

Objectives:

This study aimed to analyze scientific research trends on pleural effusions over the last decades.

Method:

We conducted a bibliometric analysis of the Scopus database from its inception to March 2016, searching for original articles and reviews on “pleural effusion” (key word). Journal, year of publication, number of citations, authors and their affiliations, and the Hirsch (H)-index for some of these variables were recorded and analyzed.

Results:

A total of 15 982 documents were retrieved, of which half have been published in the last 18 years and a quarter during the last 8 years. Chest ranked first regarding the number of documents on pleural effusions (both absolute number and yearly rate) and their scientific relevance (H-index of 76). The United States had contributed the most to pleural research productivity (23%). American pulmonologists Dr Richard Light and Dr Steven Sahn exhibited the highest number of papers (206 and 156, respectively) and author H-indexes (44 and 38, respectively).

Conclusion:

There is growing research activity in the field of pleural effusions, which has gained relevance and visibility in clinical respiratory journals. The United States is the leader in quantity and quality of research productivity in pleural medicine.

Diagnostic value of thyroid transcription factor-1 for pleural or other serous metastases of pulmonary adenocarcinoma: a meta-analysis

The role of thyroid transcription factor 1 (TTF-1) in the diagnosis of metastatic pulmonary adenocarcinomas in pleural, pericardial, and peritoneal effusions has not been defined. This study aimed to assess the overall diagnostic accuracy of TTF-1 for metastatic pulmonary adenocarcinomas in pleural or other effusions. Literature search was conducted in PubMed, EMBASE, and other databases to find eligible publications. Quality was assessed according to standardized QUADAS-2 criteria. Sensitivity, specificity, positive/negative likelihood ratio (PLR/NLR), and diagnostic odds ratio (DOR) were pooled. Summary receiver operating characteristic (SROC) curves were used to assess overall performance of the TTF-1 assay. A systematic search revealed 20 studies comprising a total of 1,213 subjects in this meta-analysis. The summary estimates were listed as follows: sensitivity, 0.74 (95% CI: 0.69–0.79); specificity, 0.99 (95% CI: 0.97–1.00); PLR, 78.16 (95% CI: 27.15–225.05); NLR, 0.26 (95% CI: 0.22–0.32); and diagnostic odds ratio, 297.75 (95% CI: 104.16–851.19). Estimated positive and negative post-probability values for metastatic pulmonary adenocarcinomas prevalence of 20% were 95% and 6%, respectively. The area under the SROC curve was 0.96. TTF-1 shows significant potential as a diagnostic marker to differentiate metastatic pulmonary from non-pulmonary adenocarcinomas in pleural or other effusions. These results justify larger, more rigorous studies to confirm such a diagnostic role.

Diagnostic performance of CD66c in lung adenocarcinoma-associated malignant pleural effusion: comparison with CEA, CA 19-9, and CYFRA 21-1

Various tumour markers have been evaluated in malignant pleural effusions, but not CD66c. This study evaluated the diagnostic ability of CD66c in lung adenocarcinoma-associated malignant pleural effusions (LA-MPEs) and compared it with other known tumour markers. Forty-seven cases of LA-MPE and 52 cases of benign pleural effusions were collected. The levels of CD66c, CEA, CA 19-9, and CYFRA 21-1 were measured by enzyme immunoassay. The expression of CD66c, CEA, and CA 19-9 in cell blocks was measured by immunocytochemistry. CEA had the best diagnostic values, with a sensitivity of 87.2% and specificity of 92.3%. Both CD66c and CA 19-9 showed the highest specificity of 98.1%, with sensitivities of 63.8% and 55.3%, respectively. CYFRA 21-1 had a sensitivity of 83.0% and specificity of 76.9%. CEA combined with CA 19-9 reached a sensitivity of 91.5% and a specificity of 98.1%. The sensitivities of immunocytochemical staining for CD66c, CEA, and CA 19-9 were 72.5%, 75%, and 40%, respectively. CD66c showed a diagnostic performance comparable to CYFRA 21-1 and CA 19-9 by enzyme immunoassay. Immunocytochemical study showed that CD66c and CEA were more sensitive than CA19-9. Both studies support CD66c as a potential tumour marker to differentiate LA-MPE from benign effusions.

Screening of carcinoma metastasis by flow cytometry: A study of 238 cases

BACKGROUND

Malignant epithelial cells may be detected in different specimens, by immunophenotyping using flow cytometry (FCM). CD326 (epithelial-specific antigen, clone Ber-Ep4) was used to identify epithelial cells, CD45 to discriminate between leucocytes (positive for this antigen) and non-hematological cells (negative for this antigen), and CD33 to identify monocytes/macrophages. This combination is particularly useful in effusions to characterize large cells and distinguish between monocyte/macrophages (CD45+ CD33+ CD326-), mesothelial cells (CD45 ± (dim) CD33 - CD326-) and epithelial cells (CD45 - CD33 - CD326 +). We evaluated the efficiency of flow cytometry to detect malignant epithelial cells in 238 fresh samples, including effusions, lymph node biopsies, fine needle aspirates, bone marrow aspirates, cerebrospinal fluid, among others. These are specimens expected to lack epithelial cells. FCM results were then compared to the results of smear and cell block morphology, as well as immunocytochemistry on paraffin wax embedded cell blocks, when available. Final diagnosis was the gold standard and a very good sensitivity (96.7%) and specificity (99.3%) were obtained. We concluded that the detection of CD326 positive cells using FCM is strongly indicative of the presence of carcinoma cells. © 2015 International Clinical Cytometry Society.

Diagnostic usefulness of MUC1 and MUC4 for distinguishing between metastatic adenocarcinoma cells and reactive mesothelial cells in effusion cell blocks

OBJECTIVE

The aim of our study was to determine the diagnostic value of MUC1 and MUC4 for distinguishing between metastatic adenocarcinoma cells (MAC) and reactive mesothelial cells (RMC) in effusion fluids.

STUDY DESIGN

A total of 237 cell block specimens from pleural and peritoneal effusions, including 196 malignant effusions with MAC and 41 benign effusions with RMC, were stained with antibodies against MUC1 and MUC4. Membranous staining with or without cytoplasmic staining was considered to be positive.

RESULTS

MUC1 immunoreactivity was observed in 194 (99.0%) of 196 cases of MAC and in 20 (48.8%) of 41 cases of RMC. MUC4 immunoreactivity was observed in 174 (88.8%) of 196 cases of MAC and in 4 (9.8%) of 41 cases of RMC. For distinguishing MAC from RMC, the MUC1 reactivity was found to be 99.0% sensitive and 51.2% specific with a positive predictive value of 90.7% and a negative predictive value of 91.3%. The sensitivity of MUC4 for MAC was 88.8%, the specificity was 90.2%, the negative predictive value was 62.7%, and the positive predictive value was 97.8%.

CONCLUSION

Our data suggest that MUC4 appears to be a sensitive and specific marker for differentiating between MAC and RMC.

Adenocarcinoma cells in effusion cytology as a diagnostic pitfall with potential impact on clinical management: a case report with brief review of immunomarkers

Distinguishing metastatic carcinoma cells from reactive mesothelial cells in effusion samples is often challenging based on morphology alone. Metastatic carcinoma cells in fluid samples may mimic reactive mesothelial cells due to overlapping cytological features. We report a case of a pleural effusion in a 51-year-old female patient with a medical history significant for bilateral ovarian tumors and peritoneal implants diagnosed as serous tumor of borderline malignant potential. The effusion was composed almost entirely of adenocarcinoma cells that morphologically mimicked reactive mesothelial cells. The diagnosis of metastatic adenocarcinoma was made after a wide immunostaining panel of antibodies. Recognizing metastatic adenocarcinoma cells in effusion samples can be challenging and an accurate diagnosis may have significant impact on clinical management as demonstrated by this case.

Pathological and molecular biological approaches to early mesothelioma

Malignant mesothelioma is an asbestos-related malignancy that arises primarily from mesothelial cells on the serosal surfaces of the pleural, peritoneal, and pericardial cavities. Malignant pleural mesothelioma (MPM) is most common, and its incidence is dramatically increasing worldwide as a result of widespread use of asbestos. Morphological discrimination between MPM and reactive mesothelial hyperplasia is difficult, and the most reliable pathological criterion for malignancy is mesothelial proliferation invading deeply into subpleural adipose tissues. To establish radical cure of MPM, it is crucial to find early-stage MPM of epithelial type, in which mesothelial proliferation is localized on the serosal surface of parietal pleura or limited within the submesothelial fibrous tissues of parietal pleura. The initial clinical presentation for patients with MPM is frequently dyspnea and/or chest pain due to large pleural effusion, and cytological analysis of pleural effusions is valuable to find patients with early-stage MPM of epithelial type. Recently, cytological features of MPM in pleural effusion, molecular markers for MPM, and genetic alternations of MPM have been reported. In this review, we discuss major issues on pathological and molecular biological approaches for diagnosis of early-stage MPM of epithelial type.

Expression of the Ets transcription factor EHF in serous ovarian carcinoma effusions is a marker of poor survival

The EHF (Ets homologous factor) gene was previously shown to be overexpressed in ovarian/primary peritoneal serous carcinoma compared to malignant mesothelioma using gene expression arrays. The objective of this study was to validate this finding at the mRNA level in a larger series. We analyzed the diagnostic role of EHF in 98 ovarian serous carcinoma effusions, 23 malignant mesothelioma specimens (20 effusions, 3 surgical specimens), and 28 primary ovarian serous carcinomas using quantitative real-time polymerase chain reaction. Expression levels of EHF in ovarian carcinoma were additionally investigated for association with clinicopathologic parameters and survival. Quantitative real-time polymerase chain reaction analysis showed significantly higher expression of EHF mRNA in ovarian carcinoma effusions and in primary ovarian carcinoma compared to malignant mesothelioma effusions (P < .001 for both). EHF mRNA expression was additionally higher in primary ovarian carcinomas compared to effusions of this cancer (P < .001). In univariate analysis for all patients with effusions, higher EHF mRNA levels were associated with a trend for shorter progression-free survival (P = .066), which became significant in analysis of 45 patients with primary diagnosis pre-chemotherapy effusions (P = .01). In Cox multivariate analysis, EHF mRNA expression was an independent predictor of poor progression-free survival for all patients and patients with primary diagnosis pre-chemotherapy effusions (P = .033 and P = .009, respectively). EHF mRNA levels differentiate ovarian carcinoma from malignant mesothelioma and may thus be of diagnostic value in this setting. EHF may be a novel prognostic marker in ovarian carcinoma.

Utility of a limited panel of calretinin and Ber-EP4 immunocytochemistry on cytospin preparation of serous effusions: A cost-effective measure in resource-limited settings

Background:

Differentiation between reactive, but morphologically atypical, mesothelial cells and adenocarcinoma in effusions can be problematic. Elaborate immunohistochemical panels have been devised. Techniques like DNA analysis, flow/image cytometry, and K-ras mutation analysis are research oriented and difficult to perform in routine, especially in resource-poor centers. We evaluated the efficacy of a limited two-antibody panel comprising calretinin and Ber-EP4 on cytospin and cell block preparations, in 100 effusion samples.

Materials and Methods:

Fifty cases of reactive mesothelial hyperplasia and 50 cases of adenocarcinoma diagnosed by cytomorphology in ascitic/pleural fluid specimens over a 2-year period were assessed. The diagnoses were confirmed by clinical/histopathologic correlation. Cytospin smears were made in all. Cell blocks were prepared, wherever adequate fluid was available. Immunocytochemistry (ICC) for calretinin and Ber-EP4 was performed.

Results:

Forty-five of the reactive effusion cases (90%) were calretinin reactive and Ber-EP4 negative. Among the adenocarcinoma cases, 49 (98%) were calretinin negative but Ber-EP4 positive. Thus, both calretinin and Ber-EP4 had a high sensitivity (90% and 98%, respectively), as well as a high specificity (100% and 86%, respectively). In the 21 reactive mesothelial cases, whose cell blocks were made, results were comparable to those on cytospin. However, of the 19 adenocarcinoma cases in which cell blocks were prepared, all were Ber-EP4 immunopositive except for three, which were positive on cytospin, implying false-negative results on cell blocks.

Conclusions:

A limited panel of two monoclonal antibodies, calretinin and Ber-EP4, may be useful in cytology, as a “primary antibody panel”, for accurate diagnosis and patient management. Additionally, ICC can be performed easily on cytospin preparations, which gave results comparable to cell blocks in our study.

PINCH-2 expression in cancers involving serosal effusions using quantitative PCR

OBJECTIVE

The PINCH-2 gene was previously shown to be overexpressed in malignant mesothelioma compared with ovarian/peritoneal serous carcinoma in Affymetrix array analysis. The objective of the present study was to validate this finding at the mRNA and protein level.

METHODS

Effusions (n = 91; 71 ovarian and 10 breast carcinomas, 10 malignant mesotheliomas) were assayed for PINCH-2 mRNA expression using quantitative PCR. PINCH-2 protein expression was analysed in 37 effusions using flow cytometry.

RESULTS

Quantitative PCR analysis showed significantly higher PINCH-2 mRNA levels in mesotheliomas compared with carcinomas (P = 0.004). Values of <10 copies were found exclusively in carcinoma effusions (25.4% of ovarian and 50% of breast carcinomas). However, PINCH-2 protein expression by flow cytometry did not differ significantly between the three cancer types. No association was observed between PINCH-2 levels and patient survival or expression of previously-studied molecules related to adhesion, metastasis and apoptosis inhibition in ovarian carcinoma.

CONCLUSIONS

Our data suggest that PINCH-2 mRNA is overexpressed in malignant mesothelioma compared with carcinomas involving serosal cavities, and that low levels of this gene argue against the diagnosis of mesothelioma. The frequent PINCH-2 protein expression in all three studied cancers suggests a role for this molecule in cancer cell biology in effusions and merits further research.

Antigen retrieval immunohistochemistry: review and future prospects in research and diagnosis over two decades

As a review for the 20th anniversary of publishing the antigen retrieval (AR) technique in this journal, the authors intend briefly to summarize developments in AR-immunohistochemistry (IHC)-based research and diagnostics, with particular emphasis on current challenges and future research directions. Over the past 20 years, the efforts of many different investigators have coalesced in extending the AR approach to all areas of anatomic pathology diagnosis and research and further have led to AR-based protein extraction techniques and tissue-based proteomics. As a result, formalin-fixed paraffin-embedded (FFPE) archival tissue collections are now seen as a literal treasure of materials for clinical and translational research to an extent unimaginable just two decades ago. Further research in AR-IHC is likely to focus on tissue proteomics, developing a more efficient protocol for protein extraction from FFPE tissue based on the AR principle, and combining the proteomics approach with AR-IHC to establish a practical, sophisticated platform for identifying and using biomarkers in personalized medicine.

Immunocytochemistry of CD146 is useful to discriminate between malignant pleural mesothelioma and reactive mesothelium

Malignant pleural mesothelioma is a refractory tumor with poor prognosis associated with asbestos exposure. Pleural effusion is frequently observed in patients with malignant pleural mesothelioma, and cytological analysis is effective to detect malignant pleural mesothelioma. However, cytological discrimination between malignant pleural mesothelioma and reactive mesothelium is often difficult. Increased expression of CD146, a cell adhesion molecule, has been reported to be closely associated with an advanced stage of malignant melanoma, prostate cancer, and ovarian cancer. In this study, to evaluate the diagnostic utility of CD146 for discrimination between malignant pleural mesothelioma and reactive mesothelium, we examined immunocytochemical expression of CD146 in malignant pleural mesothelioma and reactive mesothelium using two clones of CD146 antibody, OJ79 and EPR3208, on smear specimens of effusion fluids. Immunocytochemical stains were semiquantitatively scored on the basis of immunostaining intensity (0, negative; 1, weak positive; 2, moderate positive; and 3, strong positive). CD146 expression was detected in 15 of 16 malignant pleural mesothelioma with median immunostaining score of 3 by OJ79, and in 19 of 21 malignant pleural mesothelioma with median immunostaining score of 2 by EPR3208. Strong immunoreactivity of CD146 was observed at the apposing surfaces of cell-cell interactions on the plasma membrane of mesothelioma cells. In addition, one OJ79-negative case of malignant pleural mesothelioma was positive for CD146 by EPR3208 and two EPR3208-negative cases of malignant pleural mesothelioma were CD146 positive by OJ79, showing that all 23 malignant pleural mesothelioma cases were positive for CD146 by either OJ79 or EPR3208. On the other hand, CD146 expression was undetectable in all reactive mesothelium cases by OJ79 and EPR3208. The sensitivity of OJ79 and EPR3208 was 94 and 90%, respectively, and the specificity was 100% for both clones. We propose that CD146 is a sensitive and specific immunocytochemical marker enabling differential diagnosis of malignant pleural mesothelioma from reactive mesothelium.

Neoplastic pericardial disease: Old and current strategies for diagnosis and management

The prevalence of neoplastic pericardial diseases has changed over time and varies according to diagnostic methods. The diagnostic factor is usually the detection of neoplastic cells within the pericardial fluid or in specimens of pericardium, but the diagnosis may be difficult. Accurate sampling and cytopreparatory techniques, together with ancillary studies, including immunohistochemical tests and neoplastic marker dosage, are essential to obtain a reliable diagnosis. The goals of treatment may be simply to relieve symptoms (cardiac tamponade or dyspnea), to prevent recurrent effusion for a long-term symptomatic benefit, or to treat the local neoplastic disease with the aim of prolonging survival. Immediate relief of symptoms may be obtained with percutaneous drainage or with a surgical approach. For long term prevention of recurrences, various approaches have been proposed: extended drainage, pericardial window (surgical or percutaneous balloon pericardiostomy), sclerosing local therapy, local and/or systemic chemotherapy or radiation therapy (RT) (external or with intrapericardial radionuclides). The outcomes of various therapeutic approaches vary for different tumor types. Lymphoma and leukemias can be successfully treated with systemic chemotherapy; for solid tumors, percutaneous drainage and the use of systemic and/or local sclerosing and antineoplastic therapy seems to offer the best chance of success. The use of "pure" sclerosing agents has been replaced by agents with both sclerosing and antineoplastic activity (bleomycin or thiotepa), which seems to be quite effective in breast cancer, at least when associated with systemic chemotherapy. Local chemotherapy with platinum, mitoxantrone and other agents may lead to good local control of the disease, but the addition of systemic chemotherapy is probably relevant in order to prolong survival. The surgical approach (creation of a pericardial window, even with the mini-invasive method of balloon pericardiostomy) and RT may be useful in recurring effusions or in cases that are refractory to other therapeutic approaches.

Diagnostic value of carbohydrate antigens in supernatants and sediments of pleural effusions

A panel of tumour markers including carcinoembryonic antigen (CEA), carbohydrate antigen (Ca)15-3, Ca125 and Ca19-9 were measured in the lysate of sediments and in the supernatants of pleural effusions of patients with benign and malignant disease. The tumour markers were also measured in the serum of the same patients. Of these patients, 32 had benign diseases (12 trasudative effusions associated with cirrhosis and 20 with non-malignant exudates: 12 pleuritis and 8 other inflammations) and 103 had malignant effusions (37 breast cancers, 29 lung cancers, 10 ovary cancers, 6 kidney cancers, 11 mesotheliomas and 10 lymphomas). We showed the highest level of CEA in pleural effusions of lung cancer followed by that in pleural effusions of breast cancer; whereas Ca15-3 was very high in the pleural effusions of breast and lung cancer. Concerning the lysate of sediment, CEA was high in the pleural effusions of patients with lung cancer and Ca15-3 in those of patients with breast cancer. The other markers are much less useful. For the remaining tumours, none of the markers tested appear to aid in the diagnosis of disease. In conclusion, our data suggest that the combined determination of tumour markers on supernatants and sediments of pleural effusion may provide additional information on the nature of pleural effusion, especially for cases with negative cytology.