Adaptation of a commercial fluorescent in situ hybridization test to the diagnosis of malignant cells in effusions

Utility of BerEp4/calretinin and desmin/epithelial membrane antigen (EMA) dual immunocytochemical staining in effusion cytology

BACKGROUND

Pleural mesothelioma (PM) is typically diagnosed late during the disease. Earlier detection can increase the chance of effective therapy. Recurrent pleural effusions are the earliest symptoms displaying an array of cytomorphological changes from reactive atypia to malignancy. Diagnosis is possible on effusion cytology by applying molecular and immunocytochemical markers, the main difficulty being when to suspect PM and to differentiate PM from metastatic adenocarcinoma and reactive mesothelial proliferations.

METHODS

We evaluated the diagnostic performance of two immunocytochemical dual stains (BerEp4/Calretinin and Desmin/Epithelial Membrane Antigen (EMA)) on 149 ethanol-fixed cytospin preparation as an initial step to solve the mentioned diagnostic difficulty. The immunocytochemical reactivity pattern was evaluated by two independent investigators. The final diagnosis corresponded to PM (n = 20), metastatic adenocarcinoma (n = 83), and mesotheliosis (n = 46) in these cases.

RESULTS

Calretinin had 99% specificity and 98% sensitivity for indicating a mesothelial phenotype, while BerEp4 distinguished the adenocarcinoma cases with 98% specificity and 99% sensitivity. EMA displayed 96% specificity and 99% sensitivity in malignant cases, while Desmin without EMA present showed 99% specificity and 96% sensitivity for indicating benign mesothelial proliferation.

CONCLUSIONS

Interpretation of the four immunoreactions is improved when performed as dual stains. The dual staining is a useful tool in the initial handling of atypical effusions and guides the subsequent choice of antibody panels for more detailed subclassification of malignant effusions.

Integrative approach to cytologic and molecular diagnosis of malignant pleural mesothelioma

The global incidence of malignant mesothelioma (MM) causes considerable disease burden, suffering and health care costs. Beside preventive measures and ban the use of asbestos, early diagnosis would largely improve the chance of curative treatment. Current histologic criteria, however, requiring presence of invasion in the surrounding fatty tissue fail to identify MM in sufficiently early stage. Unilateral accumulation of pleural effusion is one of the earliest clinical manifestations of MM that occurs in approximately 90% of the patients. Therapeutic thoracocenthesis is necessary to remove the fluid and to relieve patients’ symptoms. This effusion is easily accessible and offers early and minimally invasive diagnosis by combining cytology with immunologic, molecular- and biomarker analyses. Typically, the fluid is rich in malignant cells and cell groups, but incipient stages of the disease may be difficult to recognize as the malignant cells can be masked by presence of inflammatory or reactive mesothelial cells. Recurrent, hemorrhagic and cell rich effusion should always be suspicious for MM and adequately prepared and analyzed to provide necessary information for subsequent therapy. Importantly, early detection of MM by integrating cytology and molecular approaches has high sensitivity and positive predictive value and has a major impact on patient survival. Thus, a conclusive positive MM cytology should lead to treatment without delay. This review summarizes molecular and diagnostic criteria of MM diagnosis.

Current applications of molecular testing on body cavity fluids

INTRODUCTION

Effusion cytology has a high sensitivity for the diagnosis of malignancy and provides abundant material for molecular testing. Effusion draining is a minimally invasive procedure with few complications.

MATERIALS AND METHODS

We performed a review of publications regarding the use of molecular testing in serous effusions.

RESULTS

In diagnostics, BAP-1 IHC and CDKN2A FISH are powerful tools for the diagnosis of malignant mesothelioma. FISH, PCR, and EBER-ISH work well in lymphomas. RT-PCR may enhance the diagnosis of secondary epithelial malignancies. In theranostics, molecular testing on serous effusions is widely reported for the detection of alterations in genes related to lung carcinomas, such as EGFR, ALK, ROS1, and BRAF. PD-L1 expression testing by immunohistochemistry (IHC) also seems to be viable in this type of sample. HER2 FISH and IHC provide actionable results in the context of breast malignancies. Results in serous effusions seem to be equivalent to tissue biopsies for most applications and across different molecular techniques. The most interesting technology is next-generation sequencing (NGS), given its ability to sequence multiple genes on a single sample and the decreasing costs that have closely followed increasing throughputs. Cell-free DNA from effusion supernatants might be the most promising area for future research, showing superiority to serum and even to cell-block samples in limited studies.

CONCLUSIONS

Molecular tests are viable in serous effusion specimens when sufficient material is available. Given the rising importance of molecular testing we expect this to be an active field of research in the near future.

Effusion cytology of malignant mesothelioma enables earlier diagnosis and recognizes patients with better prognosis

A conclusive diagnosis of malignant mesothelioma (MM) can be based on effusion cytology using the guidelines for the cytopathologic diagnosis of epithelioid and mixed-type MM. Briefly, the diagnosis is obtained when the mesothelial phenotype of malignant cells is established by ancillary techniques. This study is based on the comparison of the overall survival rates of patients with MM when diagnosed by effusion cytology, histopathology, or a combination of both. A total of 144 patients were diagnosed with epithelioid and mixed-type pleural MM at Karolinska University Hospital between 2004 and 2013. The diagnosis was obtained by histopathology in 74 cases and by cytological examination of pleural effusion in 70 cases. In 29 of the latter cases, a diagnostic biopsy was obtained simultaneously. A total of 104 patients received chemotherapy. All diagnoses were supported by clinical findings, including computer tomography scans. The median time between first symptoms and diagnosis was similar for cytology and histopathology. However, a delay of more than 6 months after first symptoms was seen in many patients in the histopathology group, resulting in late onset of treatment. The overall survival and proportion of long-term survival were significantly better for cases diagnosed by cytology. Similarly, a better survival, following a cytological diagnosis, was also seen in patients who were only provided the best supportive care. Accurate cytological diagnosis enables conclusive diagnosis of MM. Our finding enables the initiation of treatment as soon as the cytological diagnosis is established, avoiding further delay and deterioration of patient survival and possibilities for treatment.

CDKN2A copy number and p16 expression in malignant pleural mesothelioma in relation to asbestos exposure

Background

Deletion of the CDKN2A locus is centrally involved in the development of several malignancies. In malignant pleural mesothelioma (MPM), it is one of the most frequently reported genomic alteration. MPM is strongly associated with a patients’ asbestos exposure. However, the status of CDKN2A and the expression of the corresponding protein, p16, in relation to MPM patient’s asbestos exposure is poorly known. Copy number alterations in 2p16, 9q33.1 and 19p13 have earlier been shown to accumulate in lung cancer in relation to asbestos exposure but their status in MPM is unclear.

Methods

We studied DNA copy numbers for CDKN2A using fluorescence in situ hybridization (FISH) and p16 expression by immunohistochemistry (IHC) in 92 MPM patients, 75 of which with known asbestos exposure status. We also studied, in MPM, copy number alterations in 2p16, 9q33.1 and 19p13 by FISH.

Results

We were unable to detect an association between p16 expression and pulmonary asbestos fiber count in MPM tumor cells. However, significantly more MPM patients with high pulmonary asbestos fiber count (> 1 million fibers per gram [f/g]) had stromal p16 immunoreactivity than MPM of patients with low exposure (≤ 0.5 million f/g) (51.4% vs 16.7%; p = 0.035, Chi-Square). We found that an abnormal copy number of CDKN2A in MPM tumor cells associated with a high pulmonary asbestos fiber count (p = 0.044, Fisher’s Exact test, two-tailed). In contrast to our earlier findings in asbestos associated lung cancer, DNA copy number changes in 2p16, 9q33 and 19p13 were not frequent in MPM although single cases with variable copy numbers on those regions were seen.

Conclusions

We found two instances where the gene locus CDKN2A or its corresponding protein expression, is associated with high asbestos exposure levels. This suggests that there may be biological differences between the mesotheliomas with high pulmonary asbestos fiber count and those with low fiber count.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5652-y) contains supplementary material, which is available to authorized users.

Management of cytological material, pre-analytical procedures and bio-banking in effusion cytopathology

Serous effusion fluid is one of the most commonly encountered specimens in routine cytopathology practice. It provides invaluable information about the patient and the clinical status; but to get the most of it, specimen handling and processing must be carried out properly. Cytomorphology is the basis of a successful analysis which should complemented by ancillary tests when needed. A wide spectrum of ancillary techniques - ranging from immunocytochemistry and flow cytometry to different assays of molecular pathology - can be applied to serous effusions. This article describes the acquisition and management of serous effusion fluids, methods for preservation and transportation, different techniques of cytopreparation, application of immunocytochemistry, flow cytometry, and fluorescence in-situ hybridization (FISH), as well as DNA extraction for polymerase chain reaction (PCR) and next generation sequencing (NGS). Principles of bio-banking of effusion samples are also discussed which is getting more important in correlation with the developments in personalized medicine.

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.

Expectations and Projections for the Future of Nongynecolgical Cytology 10 Years Ago: Did They Materialize and How Did We Do?

In 2007, an article entitled "How Technology Is Reshaping the Practice of Nongynecologic Cytology: Frontiers of Cytology Symposium" [Bibbo: Acta Cytol 2007;51:123-152] was published. The moderator and editor was Marluce Bibbo, previous Editor-in-Chief of Acta Cytologica, and 17 participants from countries throughout the world were asked to answer how new technologies were being applied in their respective laboratories and whether future advances and challenges can be predicted. Ten years later, two previous participants in this Golden Anniversary Cytology Symposium were asked by Kari Syrjänen, current Editor-in-Chief of Acta Cytologica, to make a reappraisal of the 2007 predictions.

Guidelines for Pathologic Diagnosis of Malignant Mesothelioma 2017 Update of the Consensus Statement From the International Mesothelioma Interest Group

CONTEXT

- Malignant mesothelioma (MM) is an uncommon tumor that can be difficult to diagnose.

OBJECTIVE

- To provide updated, practical guidelines for the pathologic diagnosis of MM.

DATA SOURCES

- Pathologists involved in the International Mesothelioma Interest Group and others with an interest and expertise in the field contributed to this update. Reference material included up-to-date, peer-reviewed publications and textbooks.

CONCLUSIONS

- There was discussion and consensus opinion regarding guidelines for (1) distinguishing benign from malignant mesothelial proliferations (both epithelioid and spindle cell lesions), (2) cytologic diagnosis of MM, (3) recognition of the key histologic features of pleural and peritoneal MM, (4) use of histochemical and immunohistochemical stains in the diagnosis and differential diagnosis of MM, (5) differentiating epithelioid MM from various carcinomas (lung, breast, ovarian, and colonic adenocarcinomas, and squamous cell and renal cell carcinomas), (6) diagnosis of sarcomatoid MM, (7) use of molecular markers in the diagnosis of MM, (8) electron microscopy in the diagnosis of MM, and (9) some caveats and pitfalls in the diagnosis of MM. Immunohistochemical panels are integral to the diagnosis of MM, but the exact makeup of panels employed is dependent on the differential diagnosis and on the antibodies available in a given laboratory. Depending on the morphology, immunohistochemical panels should contain both positive and negative markers for mesothelial differentiation and for lesions considered in the differential diagnosis. Immunohistochemical markers should have either sensitivity or specificity greater than 80% for the lesions in question. Interpretation of positivity generally should take into account the localization of the stain (eg, nuclear versus cytoplasmic) and the percentage of cells staining (>10% is suggested for cytoplasmic and membranous markers). Selected molecular markers are now being used to distinguish benign from malignant mesothelial proliferations. These guidelines are meant to be a practical diagnostic reference for the pathologist; however, some new pathologic predictors of prognosis and response to therapy are also included.

Common Fluorescence In Situ Hybridization Applications in Cytology

Context.—

Fluorescence in situ hybridization (FISH) is a well-established method for detection of genomic aberrations in diagnostic, prognostic, and predictive marker testing.

Objective.—

To review common applications of FISH in cytology.

Data Sources.—

The published literature was reviewed.

Conclusions.—

Cytology is particularly well suited for all kinds of FISH applications, which is highlighted in respiratory tract cytology with an increasing demand for predictive FISH testing in lung cancer. Fluorescence in situ hybridization is the gold standard for detection of predictive anaplastic lymphoma kinase gene (ALK) rearrangements, and the same evaluation criteria as in histology apply to cytology. Several other gene rearrangements, including ROS proto-oncogene 1 receptor tyrosine kinase (ROS1), are becoming clinically important and share the same underlining cytogenetic mechanisms with ALK. MET amplification is one of the most common mechanisms of acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors and can be targeted by crizotinib. As genomic aberrations are a hallmark of malignant cells, FISH is a valuable objective ancillary diagnostic tool. In urinary tract cytology, atypical urothelial cells equivocal for malignancy are a common diagnostic dilemma and multitarget FISH can help clarify such cells. Diagnosis of malignant mesothelioma remains one of the most challenging fields in effusion cytology, and ancillary FISH is useful in establishing the diagnosis. Fluorescence in situ hybridization is a morphology-based technique, and the prerequisite for reliable FISH results is a targeted evaluation of the cells in question (eg, cancer or atypical cells). Cytopathologists and cytotechnicians should therefore be involved in molecular testing in order to select the best material and to provide their morphologic expertise.

Use of p16 FISH for differential diagnosis of mesothelioma in smear preparations

Because most of malignant pleural mesothelioma (MPM) patients first present with pleural effusion, detection of mesothelioma cells on effusion smears is critical for early diagnosis. Recently, accumulating evidence indicating that the cytological diagnosis of MPM supported by ancillary techniques is as reliable as that based on histopathology has led to new guidelines for the cytopathologic diagnosis of MPM. Based on the guidelines, a combination of cytomorphological criteria and verification by ancillary techniques is required for the cytologic diagnosis of MPM. Detection of p16 homozygous deletion by fluorescence in situ hybridization (FISH) is the most reliable ancillary technique for differentiating MPM from reactive mesothelial cells (RMC) because of its relatively high sensitivity and extremely high specificity. We showed that the p16 deletion status of MPM cells in pleural effusions reflected that of the underlying invasive MPM tissues, indicating the usefulness of p16 FISH in effusion smear cytology for MPM diagnosis. Thus, for differentiating MPM from RMC, we propose to perform p16 FISH as often as possible. A positive p16 homozygous deletion supports the diagnosis of MPM. However, a negative result does not rule out the possibility of MPM. In such cases, a morphological assessment is critical. Therefore, we analyzed the morphological characteristics of p16 deletion-positive mesothelioma cells using a combination of virtual microscopy and p16 FISH, and identified three morphological characteristics useful for the differentiation, including cell-in-cell engulfment with or without hump formation, multinucleate cells, and larger berry-like cell aggregates. Diagn. Cytopathol. 2016;44:774-780. © 2016 Wiley Periodicals, Inc.

Pre-analytical issues in effusion cytology

Effusions or body cavity fluids are amongst the most commonly submitted samples to the cytology laboratory. Knowledge of proper collection, storage, preservation and processing techniques is essential to ensure proper handling and successful analysis of the sample. This article describes how the effusions should be collected and proper conditions for submission. The different processing techniques to extract the cellular material and prepare slides satisfactory for microscopic evaluation are described such as direct smears, cytospins, liquid based preparations and cell blocks. The article further elaborates on handling the specimens for additional ancillary testing such as immunostaining and molecular tests, including predictive ones, as well as future research approaches.

Guidelines for the Cytopathologic Diagnosis of Epithelioid and Mixed-Type Malignant Mesothelioma: a secondary publication

OBJECTIVE

To provide practical guidelines for the cytopathologic diagnosis of malignant mesothelioma.

DATA SOURCES

Cytopathologists with an interest in the field involved in the International Mesothelioma Interest Group (IMIG) and the International Academy of Cytology (IAC) contributed to this update. Reference material includes peer-reviewed publications and textbooks.

RATIONALE

This article is the result of discussions during and after the IMIG 2012 conference in Boston, followed by thorough discussions during the 2013 IAC meeting in Paris. Additional contributions have been obtained from cytopathologists and scientists who could not attend these meetings, with final discussions and input during the IMIG 2014 conference in Cape Town.

Guidelines for the cytopathologic diagnosis of epithelioid and mixed-type malignant mesothelioma: Complementary Statement from the International Mesothelioma Interest Group, Also Endorsed by the International Academy of Cytology and the Papanicolaou Society of Cytopathology

OBJECTIVE

To provide practical guidelines for the cytopathologic diagnosis of malignant mesothelioma.

DATA SOURCES

Cytopathologists with an interest in the field involved in the International Mesothelioma Interest Group (IMIG) and the International Academy of Cytology (IAC) contributed to this update. Reference material includes peer-reviewed publications and textbooks.

RATIONALE

This article is the result of discussions during and after the IMIG 2012 conference in Boston, followed by thorough discussions during the 2013 IAC meeting in Paris. Additional contributions have been obtained from cytopathologists and scientists who could not attend these meetings, with final discussions and input during the IMIG 2014 conference in Cape Town.

Guidelines for cytopathologic diagnosis of epithelioid and mixed type malignant mesothelioma. Complementary statement from the International Mesothelioma Interest Group, also endorsed by the International Academy of Cytology and the Papanicolaou Society of Cytopathology

To provide practical guidelines for the cytopathologic diagnosis of malignant mesothelioma (MM). Cytopathologists involved in the International Mesothelioma Interest Group (IMIG) and the International Academy of Cytology (IAC), who have an interest in the field contributed to this update. Reference material includes peer-reviewed publications and textbooks. This article is the result of discussions during and after the IMIG 2012 conference in Boston, followed by thorough discussions during the 2013 IAC meeting in Paris. Additional contributions have been obtained from cytopathologists and scientists, who could not attend these meetings, with final discussions and input during the IMIG 2014 conference in cape town. During the previous IMIG biennial meetings, thorough discussions have resulted in published guidelines for the pathologic diagnosis of MM. However, previous recommendations have stated that the diagnosis of MM should be based on histological material only.[12] Accumulating evidence now indicates that the cytological diagnosis of MM supported by ancillary techniques is as reliable as that based on histopathology, although the sensitivity with cytology may be somewhat lower.[345] Recognizing that noninvasive diagnostic modalities benefit both the patient and the health system, future recommendations should include cytology as an accepted method for the diagnosis of this malignancy.[67] The article describes the consensus of opinions of the authors on how cytology together with ancillary testing can be used to establish a reliable diagnosis of MM.

Guidelines for the cytopathologic diagnosis of epithelioid and mixed-type malignant mesothelioma. Complementary statement from the International Mesothelioma Interest Group, also endorsed by the International Academy of Cytology and the Papanicolaou Society of Cytopathology

OBJECTIVE

To provide practical guidelines for the cytopathologic diagnosis of malignant mesothelioma.

DATA SOURCES

Cytopathologists with an interest in the field involved in the International Mesothelioma Interest Group (IMIG) and the International Academy of Cytology (IAC) contributed to this update. Reference material includes peer-reviewed publications and textbooks.

RATIONALE

This article is the result of discussions during and after the IMIG 2012 conference in Boston, followed by thorough discussions during the 2013 IAC meeting in Paris. Additional contributions have been obtained from cytopathologists and scientists who could not attend these meetings, with final discussions and input during the IMIG 2014 conference in Cape Town.

Characterization and drug sensitivity profiling of primary malignant mesothelioma cells from pleural effusions

Background

Patients with malignant mesothelioma have a poor prognosis and only 40% respond to first line treatment; a combination of pemetrexed and cisplatin or carboplatin. We used primary malignant mesothelioma cells and an ex vivo chemosensitivity assay with future purpose to predict best choice of treatment. The clinical outcome of these patients might be predicted by measuring drug sensitivity.

Methods

Pleural effusions containing primary malignant mesothelioma cells were received from the diagnostic routine. We characterized and tested the chemosensitivity of 18 malignant samples and four benign samples from 16 different patients with pleural effusions. Cells were seeded in a 384-well plate for a robotized ex vivo testing of drug sensitivity to 32 different drugs. The primary cells were further characterized by immunocytochemistry to evaluate the proportion of malignant cells and to study the RRM1 and ERCC1 reactivity, two proteins associated with drug resistance.

Results

We observed great individual variability in the drug sensitivity. Primary cell isolates were affected by between one and ten drugs, and resistant to the remaining tested drugs. Actinomycin D and daunorubicin were the two drugs effective in most cases. Adjusting efficiency of individual drugs for varying proportion of tumor cells and to the average effect on benign cells correlated with effect of pemetrexed, cisplatin and survival time. General drug sensitivity, proportion of malignant cells and reactivity to RRM1 correlated to each other and to survival time of the patients.

Conclusions

The proportion of malignant cells and RRM1 reactivity in the pleural effusions correlate to drug sensitivity and survival time. The variability in response to the commonly used chemotherapies emphasizes the need for tests that indicate best individual choice of cytotoxic drugs. The efficiency of the obtained results should preferably be corrected for admixture of benign cells and effects of given drugs on benign cells.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-709) contains supplementary material, which is available to authorized users.

[Pleural mesothelioma. Cytology and molecular diagnostics]

The definitive diagnosis of malignant mesothelioma (MM) in effusion cytology is often avoided or reluctantly made by cytology alone. The most probable reason for this skepticism is the lack of expertise in cytology among many pathologists and clinicians. When an effusion specimen is composed of cells with unequivocal cytological features of malignancy that have the morphology and immunophenotype of mesothelial cells, the cytological diagnosis of MM is straightforward. However, in the daily routine difficult cases of atypical mesothelial cells are often encountered and additional methods are required to establish an accurate diagnosis. In contrast to reactive mesothelial cells cells of MMs often harbor chromosomal aberrations, most frequently a polysomy in combination with a 9p21 deletion. These chromosomal aberrations can easily be detected by multitarget fluorescence in situ hybridization (FISH); therefore, FISH allows a reliable distinction between reactive mesothelial cells and MM cells. In order to be able to discriminate between MM and adenocarcinoma, an immunocytochemical panel consisting of different mesothelial and epithelial markers is very helpful. In most inconclusive cases of atypical mesothelial cells the combination of morphology, immunocytochemistry and FISH allows a better distinction between reactive mesothelial cells and MM in effusion cytology.

BMVC test, an improved fluorescence assay for detection of malignant pleural effusions

The diagnosis of malignant pleural effusions is an important issue in the management of malignancy patients. Generally, cytologic examination is a routine diagnostic technique. However, morphological interpretation of cytology is sometimes inconclusive. Here an ancillary method named BMVC test is developed for rapid detection of malignant pleural effusion to improve the diagnostic accuracy at low cost. A simple assay kit is designed to collect living cells from clinical pleural effusion and a fluorescence probe, 3,6-Bis(1-methyl-4-vinylpyridinium) carbazole diiodide (BMVC), is used to illuminate malignant cells. The fluorescence intensity is quantitatively analyzed by ImageJ program. This method yields digital numbers for the test results without any grey zone or ambiguities in the current cytology tests due to intra-observer and inter-observer variability. Comparing with results from double-blind cytologic examination, this simple test gives a good discrimination between malignant and benign specimens with sensitivity of 89.4% (42/47) and specificity of 93.3% (56/60) for diagnosis of malignant pleural effusion. BMVC test provides accurate results in a short time period, and the digital output could assist cytologic examination to become more objective and clear-cut. This is a convenient ancillary tool for detection of malignant pleural effusions.

Hyaluronan and N-ERC/mesothelin as key biomarkers in a specific two-step model to predict pleural malignant mesothelioma

Purpose

Diagnosis of malignant mesothelioma is challenging. The first available diagnostic material is often an effusion and biochemical analysis of soluble markers may provide additional diagnostic information. This study aimed to establish a predictive model using biomarkers from pleural effusions, to allow early and accurate diagnosis.

Patients and Methods

Effusions were collected prospectively from 190 consecutive patients at a regional referral centre. Hyaluronan, N-ERC/mesothelin, C-ERC/mesothelin, osteopontin, syndecan-1, syndecan-2, and thioredoxin were measured using ELISA and HPLC. A predictive model was generated and validated using a second prospective set of 375 effusions collected consecutively at a different referral centre.

Results

Biochemical markers significantly associated with mesothelioma were hyaluronan (odds ratio, 95% CI: 8.82, 4.82–20.39), N-ERC/mesothelin (4.81, 3.19–7.93), CERC/mesothelin (3.58, 2.43–5.59) and syndecan-1 (1.34, 1.03–1.77). A two-step model using hyaluronan and N-ERC/mesothelin, and combining a threshold decision rule with logistic regression, yielded good discrimination with an area under the ROC curve of 0.99 (95% CI: 0.97–1.00) in the model generation dataset and 0.83 (0.74–0.91) in the validation dataset, respectively.

Conclusions

A two-step model using hyaluronan and N-ERC/mesothelin predicts mesothelioma with high specificity. This method can be performed on the first available effusion and could be a useful adjunct to the morphological diagnosis of mesothelioma.

Microenvironment-Dependent Phenotypic Changes in a SCID Mouse Model for Malignant Mesothelioma

Background and Aims: Malignant mesothelioma is an aggressive, therapy-resistant tumor. Mesothelioma cells may assume an epithelioid or a sarcomatoid phenotype, and presence of sarcomatoid cells predicts poor prognosis. In this study, we investigated differentiation of mesothelioma cells in a xenograft model, where mesothelioma cells of both phenotypes were induced to form tumors in severe combined immunodeficiency mice.

Methods: Xenografts were established and thoroughly characterized using a comprehensive immunohistochemical panel, array comparative genomic hybridization (aCGH) of chromosome 3, fluorescent in situ hybridization, and electron microscopy.

Results: Epithelioid and sarcomatoid cells gave rise to xenografts of similar epithelioid morphology. While sarcomatoid-derived xenografts had higher growth rates, the morphology and expression of differentiation-related markers was similar between xenografts derived from both phenotypes. aCGH showed a convergent genotype for both xenografts, resembling the original aggressive sarcomatoid cell sub-line.

Conclusion: Human mesothelioma xenografts from sarcomatoid and epithelioid phenotypes converged to a similar differentiation state, and genetic analyses suggested that clonal selection in the mouse microenvironment was a major contributing factor. This thoroughly characterized animal model can be used for further studies of molecular events underlying tumor cell differentiation.

Diagnostic value of fluorescence in situ hybridization assay in malignant mesothelioma: a meta-analysis

The diagnosis of malignant mesothelioma (MM) remains a clinical challenge and the fluorescence in situ hybridization (FISH) assay has been reported to be one promising tool. The present meta-analysis aimed to establish the overall diagnostic accuracy of FISH for diagnosing MM. After a systematic review of English language studies, the sensitivity, specificity and other measures of accuracy of FISH in the diagnosis of MM were pooled using random-effects models. Summary receiver operating characteristic curves were applied to summarize overall test performance. Nine studies met our inclusion criteria, the pooled sensitivity and specificity for FISH for diagnosing MM being 0.72 (95% CI 0.67-0.76) and 1.00 (95% CI 0.98-1.00), respectively. The positive likelihood ratio was 34.5 (95% CI 14.5-82.10), the negative likelihood ratio was 0.24 (95% CI 0.16-0.36), and the diagnostic odds ratio was 204.9 (95% CI 76.8-546.6), the area under the curve being 0.99. Our data suggest that the FISH assay is likely to be a useful diagnostic tool for confirming MM. However, considering the limited studies and patients included, further large scale studies are needed to confirm these findings.

Current and future options for the diagnosis of malignant pleural effusion

INTRODUCTION

Malignant pleural effusion (MPE) is a frequent problem faced by clinicians, but tumor pleural involvement can be seen without effusion.

AREAS COVERED

Imaging, pleural fluid analysis, biomarkers for MPE, needle pleural biopsy and thoracoscopy. To prepare this review, we performed a search using keywords: 'diagnosis' + 'malignant' + 'pleural' + 'effusion' (all fields) in PubMed, and found 4106 articles overall (until 16 January 2013, 881 in the last 5 years).

EXPERT OPINION

Ultrasound techniques will stay as valuable tools for pleural effusions. Biomarkers in pleural fluid do not currently provide an acceptable yield for MPE. In subjects with past history of asbestos exposure, some serum or plasma markers (soluble mesothelin, fibulin) might help in selecting cases for close follow-up, to detect mesothelioma early. Needle pleural biopsy is justified only if used with image-techniques (ultrasound or CT) guidance, and thoracoscopy is better for both diagnosis and immediate palliative treatment (pleurodesis). Animal models of MPE and 'spheroids' are promising for research involving both pathophysiology and therapy. Considering the possibility of direct pleural delivery of nanotechnology-developed compounds-fit to both diagnosis and therapy purposes ('theranostics')-MPE and mesothelioma in particular are likely to benefit sooner than later from this exciting perspective.

Efficacy of two fluorescence in situ hybridization (FISH) probes for diagnosing malignant pleural effusions

It is difficult to differentiate tumor cells in pleural fluid from reactive benign mesothelium. Fluorescence in situ hybridization (FISH) can increase diagnostic accuracy. Two hundred pleural fluid samples were analyzed by using FISH probes for chromosomes 11 and 17. Histological analysis was used to diagnose cancer. Clinical, radiological, and histological data were used to exclude malignancy. Eighty-two pleural effusion samples had positive cytology, 51 were benign, and 67 were atypical, but inconclusive. The 82 positive cases were confirmed to be malignant. Among the 51 negative cytology cases, videothoracoscopy-guided pleural biopsy revealed malignancy in three; aneuploid cells were detected by FISH in all cases. In 43 of the 67 cases with inconclusive cytology, malignancy was confirmed based on histology and fluorescence in situ hybridization. One case of parapneumonic effusion with no evidence of cancer during clinical follow-up had a suspicious cytology and positive fluorescence in situ hybridization result. The remaining 23 cases had no histological, radiological, clinical, or genetic evidence of malignancy. This study demonstrated that cytogenetic analysis of fresh pleural fluid samples using only two FISH probes is a valuable ancillary method for the identification of malignant pleural effusion, particularly in cases in which oncotic cytology is inconclusive.

Guidelines for pathologic diagnosis of malignant mesothelioma: 2012 update of the consensus statement from the International Mesothelioma Interest Group

CONTEXT

Malignant mesothelioma (MM) is an uncommon tumor that can be difficult to diagnose.

OBJECTIVE

To provide updated practical guidelines for the pathologic diagnosis of MM.

DATA SOURCES

Pathologists involved in the International Mesothelioma Interest Group and others with an interest in the field contributed to this update. Reference material includes peer-reviewed publications and textbooks.

CONCLUSIONS

There was consensus opinion regarding (1) distinction of benign from malignant mesothelial proliferations (both epithelioid and spindle cell lesions), (2) cytologic diagnosis of MM, (3) key histologic features of pleural and peritoneal MM, (4) use of histochemical and immunohistochemical stains in the diagnosis and differential diagnosis of MM, (5) differentiation of epithelioid MM from various carcinomas (lung, breast, ovarian, and colonic adenocarcinomas, and squamous cell and renal cell carcinomas), (6) diagnosis of sarcomatoid mesothelioma, (7) use of molecular markers in the diagnosis of MM, (8) electron microscopy in the diagnosis of MM, and (9) some caveats and pitfalls in the diagnosis of MM. Immunohistochemical panels are integral to the diagnosis of MM, but the exact makeup of panels used is dependent on the differential diagnosis and on the antibodies available in a given laboratory. Immunohistochemical panels should contain both positive and negative markers. It is recommended that immunohistochemical markers have either sensitivity or specificity greater than 80% for the lesions in question. Interpretation of positivity generally should take into account the localization of the stain (eg, nuclear versus cytoplasmic) and the percentage of cells staining (>10% is suggested for cytoplasmic membranous markers). These guidelines are meant to be a practical reference for the pathologist.

Chromosomal abnormalities in renal cell carcinoma variants detected by Urovysion fluorescence in situ hybridization on paraffin-embedded tissue

Urovysion fluorescence in situ hybridization (UVFISH) identifies malignant cells in urine by detecting specific urothelial carcinoma-related chromosomal abnormalities. Some renal carcinomas (RCCs) share overlapping chromosomal aberrations with urothelial carcinoma. Malignant renal cells that are shed in urine can potentially cause a positive UVFISH result. We evaluated UVFISH in RCCs to determine its potential applicability to the diagnosis and grading of RCCs. Paraffin blocks from 39 RCCs (25 clear cell, 9 papillary, 2 chromophobe, and 3 sarcomatoid) and 15 controls (5 renal oncocytomas and 10 urothelial carcinomas) were tested. Of the RCCs, 15 (40%) were UVFISH-positive (9/25 [40%] clear cell, 3/9 [30%] papillary, 1/2 [50%] chromophobe, and 2/3 [67%] sarcomatoid carcinoma) and 24 (60%) were negative. Of the 15 controls, 8 (∼50%) were UVFISH-positive (2/5 [40%] oncocytomas and 6/10 [60%] urothelial carcinomas) and 7 (∼50%) were UVFISH-negative. Polysomy of chromosome 17 showed a statistically significant correlation with RCC subtype, being absent in most of the clear cell RCCs (P = .0096) compared with other RCCs. Polysomy of chromosome 7 was more frequent in high-grade than low-grade RCC (P = .0197) and more likely in high-grade clear cell than low-grade clear cell RCC (P = .0120). In conclusion, we showed that RCC has overlapping chromosomal abnormalities with urothelial carcinoma and can cause a positive UVFISH result. This has implications for the interpretation of Urovysion in patients whose urine contains malignant cells but who have negative cystoscopy and a concomitant renal mass. The chromosomal abnormalities observed in RCC are not distinct from those in urothelial carcinoma; therefore, UVFISH cannot distinguish these tumor types, nor can it type or grade RCC.

Factors that impact susceptibility to fiber-induced health effects

Asbestos and related fibers are associated with a number of adverse health effects, including malignant mesothelioma (MM), an aggressive cancer that generally develops in the surface serosal cells of the pleural, pericardial, and peritoneal cavities. Although approximately 80% of individuals with MM are exposed to asbestos, fewer than 5% of asbestos workers develop MM. In addition to asbestos, other mineralogical, environmental, genetic, and possibly viral factors might contribute to MM susceptibility. Given this complex etiology of MM, understanding susceptibility to MM needs to be a priority for investigators in order to reduce exposure of those most at risk to known environmental carcinogens. In this review, the current body of literature related to fiber-associated disease susceptibility including age, sex, nutrition, genetics, asbestos, and other mineral exposure is addressed with a focus on MM, and critical areas for further study are recommended.

Genetically abnormal circulating cells in lung cancer patients: an antigen-independent fluorescence in situ hybridization-based case-control study

PURPOSE

We performed a study to determine if a fluorescence in situ hybridization (FISH)-based assay using isolated peripheral blood mononuclear cells (PBMCs) with DNA probes targeting specific sites on chromosomes known to have abnormalities in non-small cell lung cancer (NSCLC) cases could detect circulating genetically abnormal cells (CACs).

EXPERIMENTAL DESIGN

We evaluated 59 NSCLC cases with stage I through IV disease and 24 controls. PBMCs and matched tumors were hybridized with 2 two-color [3p22.1/CEP3 and 10q22.3 (SP-A)/CEP10) and 2 four-color [CEP3, CEP7, CEP17, and 9p21.3 (URO); and EGFR, c-MYC, 6p11-q11, and 5p15.2 (LAV)] FISH probes. Percentages of cytogenetically abnormal cells (CACs) in peripheral blood and in matched tumor specimens were quantified by using an automated fluorescent scanner. Numbers of CACs were calculated based on the percentage of CACs (defined as PBMCs with genetic abnormalities) per milliliter of blood and expressed per microliter of blood.

RESULTS

Patients with NSCLC had significantly higher numbers of CACs than controls. Mean number of CACs ranged from 7.23 +/- 1.32/microL for deletions of 10q22.3/CEP10 to 45.52 +/- 7.49/microL for deletions of 3p22.1/CEP3. Numbers of CACs with deletions of 3p22.1, 10q22.3, and 9p21.3, and gains of URO, increased significantly from early to advanced stage of disease.

CONCLUSIONS

We have developed a sensitive and quantitative antigen-independent FISH-based test for detecting CACs in peripheral blood of patients with NSCLC, which showed a significant correlation with the presence of cancer. If this pilot study can be validated in a larger study, CACs may have a role in the management of patients with NSCLC.

Benign and Malignant Mesothelial Proliferation

Malignant mesothelioma (MM) is a rare primary malignant tumor of the surface serosal cells. The diagnosis of MM is challenging with a broad differential diagnosis. For many decades, studies have focused on distinguishing MM from other types of cancer; however, benign mesothelial cell hyperplasia, especially in small biopsies, has emerged as a major problem. The features of pleural lesions are somewhat different from peritoneal diseases, and this article primarily focuses on pleural diseases. Thorough interpretation and correlation of clinical, radiologic, and pathologic findings are essential for a correct diagnosis.