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

Application of Immunohistochemistry in Cytology

Immunohistochemistry (IHC), also referred to as immunocytochemistry in cytology literature, has revolutionized the practice of cytopathology. Because of the complexity of cytology preparation and limited diagnostic material, performing IHC remains a challenge. Formalin-fixed paraffin-embedded (FFPE) cell block (CB) is the optimal choice for IHC. In this review, the approaches for improving CB preparation will be discussed. When CB material is not available, various cytology specimens can also be used for IHC. With the utilization of Antigen Retrieval (AR) technique, these nonformalin-fixed cytology specimens can achieve successful IHC staining, comparable with the results from FFPE tissue sections. In the last part of this review, we will discuss the use of positive controls and the important role of AR in standardization of IHC in cytology.

Evaluation of cell blocks from effusion specimens in Gynecologic Oncopathology: An experience of 220 cases, diagnosed at a Tertiary Cancer Referral Center

One of the common indications of ascitic fluid examination in gynecological oncopathology is the detection and classification of malignant cells, especially in cases of clinically suspicious tubo-ovarian masses. The present study was undertaken to assess and validate the diagnostic utility of cell blocks (CBs) and compare its results with the corresponding conventional smears, prepared from effusion samples. CBs were prepared by thromboplastin technique in 220 cases. In 208 cases, diagnostic concordance between results obtained from smears and corresponding CBs was evaluated. Various antibody markers were tested, as per individual case. The average age of patients was 52.2 years. Positive immunohistochemical (IHC) staining for various markers was observed in 182 cases (82.7%) The most frequently positive antibody marker was PAX8 (101/134), followed by p53 (85/92) [mutation type (either diffusely positive or completely negative)], WT1 (tumor cells) (80/112), calretinin (2/87) (diffuse), BerEP4 (21/49), CA125 (21/24), CK7 (31/39) and CK20 and CDX2, together (5/16). Various other IHC markers utilized, including their positive expression, were TTF1 (1/10), p40 (3/3), p63 (2/4), ER (21/29), HBME1 (1/7), GATA3 (1/4), and MIC2 (1/1). Complete diagnostic concordance between CBs and smears was observed in 170/208 cases (81.7%). There were 20 major discordances, 10 minor and 8 cases with sampling errors. IHC was useful in classifying 158/182 (86.8%) cases, including serous or Müllerian adenocarcinoma (n = 123), mostly high-grade (121); metastatic squamous carcinoma (3); gastrointestinal-type adenocarcinoma (8); pulmonary adenocarcinoma (1); breast adenocarcinoma (1); Ewing sarcoma (1); and mesothelioma (2). CBs are complementary to smears in the detection of gynecological malignancies, mostly high-grade serous adenocarcinomas. These provide an opportunity for testing several IHC markers, for a precise diagnosis, including in various uncommon case scenarios, associated with significant therapeutic implications.

A Preliminary Study of Deep-Learning Algorithm for Analyzing Multiplex Immunofluorescence Biomarkers in Body Fluid Cytology Specimens

INTRODUCTION

Multiplex biomarker analysis of cytological body fluid specimens is often used to assist cytologists in distiguishing metastatic cancer cells from reactive mesothelial cells. However, evaluating biomarker expression visually may be challenging, especially when the cells of interest are scant. Deep-learning algorithms (DLAs) may be able to assist cytologists in analyzing multiple biomarker expression at the single cell level in the multiplex fluorescence imaging (MFI) setting. This preliminary study was performed to test the feasibility of using DLAs to identify immunofluorescence-stained metastatic adenocarcinoma cells in body fluid cytology samples.

METHODS

A DLA was developed to analyze MFI-stained cells in body fluid cytological samples. A total of 41 pleural fluid samples, comprising of 20 positives and 21 negatives, were retrospectively collected. Multiplex immunofluorescence labeling for MOC31, BerEP4, and calretinin, were performed on cell block sections, and results were analyzed by manual analysis (manual MFI) and DLA analysis (MFI-DLA) independently.

RESULTS

All cases with positive original cytological diagnoses showed positive results either by manual MFI or MFI-DLA, but 2 of the 14 (14.3%) original cytologically negative cases had rare cells with positive MOC31 and/or BerEP4 staining in addition to calretinin. Manual MFI analysis and MFI-DLA showed 100% concordance.

CONCLUSION

MFI combined with DLA provides a potential tool to assist in cytological diagnosis of metastatic malignancy in body fluid samples. Larger studies are warranted to test the clinical validity of the approach.

Detection of carcinoma in serous effusions: a review

A malignant serous effusion is one of the most common complications of advanced tumors, indicating a poor prognosis and having a profound impact on diagnosis, treatment, and prognosis. It is of great significance to identify benign and malignant effusions quickly and accurately. Both cellular and non-cellular components in the effusion can be employed for detection, diagnostic methods are necessary to obtain a definite diagnosis and more relevant information such as tumor classification. In this review, we focus on the comparison of several widespread cytological preparation methods, enrichment technology of exfoliated cells, and present tests for serous effusions, mainly including routine and special stains, immunocytochemistry, electron microscopy, enzyme-linked immunosorbent assay, flow cytometry, and molecular analysis.

Ber-EP4 staining in effusion cytology: A potential source of false positives

The distinction between reactive mesothelium and carcinoma in serous effusions can be very difficult. Immunocytochemistry (ICC) is the most widely used tool to improve the diagnostic accuracy of body fluid cytology, with several ICC markers being proposed. Ber-EP4 antibody has shown high sensitivity and specificity rates for diagnosing metastatic carcinoma. In our department, we have detected Ber-EP4 positivity in mesothelium in some cytological specimens. We reviewed all articles on Ber-EP4 staining in effusion cytology, summarized current findings and analyzed the staining pattern of all cases expressing Ber-EP4. Some cases showing Ber-EP4 positivity in mesothelium have been reported, most of which showed only weak Ber-EP4 staining or staining of less than 50% of mesothelial cells. However, some cases may show strong positivity both in cytological and histological specimens. Clinicians and pathologists should be aware of this source of misdiagnosis, and ICC results in mesothelium should be always interpreted cautiously and correlated with clinical tests, other ICC markers and patient's previous history.

Indian Academy of Cytologists Guidelines for Collection, Preparation, Interpretation, and Reporting of Serous Effusion Fluid Samples

Cytological examination plays an important role in the initial work-up of the serous cavity effusion fluids to find out the possible etiology as benign or malignant. Among malignant effusions, cytology is helpful in determining the exact type, site, and stage of the tumor. However, for reporting effusion cytology specimens, there is no consistent and reproducible reporting system.

Modified Liquid-Based Cytology Technique for Immunocytochemistry in Effusion Specimen

Objective:

Immunocytochemistry (ICC) of serous effusion is an important tool for the diagnosis of benign and malignant cells. Our aim was to develop a modified liquid-based cytological technique for ICC (i.e., a modified LBC).

Methods:

Serous effusions of 110 cases were collected for cytological examination: 50 were negative for malignancy albeit benign mesothelium was found, and 60 were confirmed metastatic adenocarcinoma according to the modified LBC preparation. The latter were stained for EMA, Ber-EP4, Calretinin, and p63 then interpreted by both a cytotechnologist and a pathologist. A comparative analysis of the diagnostic results was conducted.

Results:

The results of the metastatic adenocarcinoma were 100% (60/60) positive for EMA and 91.7% (55/60) positive for Ber-Ep4 but negative for calretinin and p63. Cases negative for malignancy were 100% (50/50) positive for calretinin but negative for carcinoma markers. The difference between ‘positive for metastatic adenocarcinoma’ and ‘negative for malignancy’ in ICC was statistically significant (p < 0.001).

Conclusion:

The current study demonstrated that a panel marker, comprising EMA, Ber-EP4, and calretinin can be used for differentiating between cases of metastatic adenocarcinoma and benign mesothelium. The serous effusion specimen collected by the modified LBC technique is an effective preparation method for ICC.

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.

Use of Panel of Markers in Serous Effusion to Distinguish Reactive Mesothelial Cells from Adenocarcinoma

Introduction:

Although cytological examination helps in diagnosis of malignancy in serous effusion, at times it is difficult to differentiate atypical reactive mesothelial cells from adenocarcinoma (AC) cells. To resolve this problem, various ancillary methods have been used. Immunocytochemistry (ICC) is one such commonly used technique in which various panel of antibodies has been tried. Unfortunately, so far no unique marker is available to solve this issue. Hence, the present study evaluates the efficacy of four antibody panel comprising of MOC-31, epithelial membrane antigen (EMA), calretinin (CAL), and mesothelin (MES) to solve this problem.

Materials and Methods:

Forty-two cases suspected of malignant effusion in pleural/peritoneal fluid and 42 cases of reactive effusion were included. Cytospin smears were prepared and stained with Giemsa stain for cytomorphological diagnosis. Cytospin smears and cell blocks were made forICC. ICC for MOC-31, EMA, CAL, and MES was performed.

Results:

Among the suspected malignant effusion cases, 30 cases were AC and 12 cases were suspicious for malignancy by cytomorphology. MOC31 demonstrated 100% sensitivity (Sn) and 95.24% specificity (Sp), and EMA had 88.1% Sn and 92.86% Sp for AC cases. CAL demonstrated 100% and 97.62%, and MES 97.62% and 88.1% Sn and Sp in reactive mesothelial cells, respectively.

Conclusion:

In conclusion, combination of MOC-31 and CAL as a limited panel will be helpful in giving an appropriate diagnosis in difficult cases and thereby, help in patient management. In addition, ICC on cytospin smears gave results similar to cell blocks, and if standardised cytospin is simple technique to perform, unlike cell blocks.

Diagnostic Utility of Epithelial Membrane Antigen (EMA) and Calretinin (CAL) in Effusion Cytology

INTRODUCTION

Fluid cytology and subsequent utilization of immunocytology on cell block is being used commonly for increasing the diagnostic accuracy in effusion cytology.

AIM

To do cytological analysis of fluids and evaluate the role of Epithelial Membrane Antigen (EMA) and Calretinin (CAL) to differentiate between reactive and malignant cell in pleural and peritoneal fluids.

MATERIALS AND METHODS

This was a prospective study carried out in Department of Pathology, Shri Guru Ram Rai Institue of Medical and Health Science, for a period of 18 months from January 2014 to June 2015. A total of 253 samples of pleural and peritoneal fluid were studied by May-Gruenwald-Giemsa (MGG) stain and Papanicolaou (Pap) staining. In 73 cases which were suspicious for malignancy, cell blocks were prepared and IHC was done using two immunomarkers- EMA and CAL.

RESULTS

A total of 253 cases of effusion cytology were studied out of which 73 were found positive for malignant cells. Maximum cases of malignant cells or atypical cells were seen in peritoneal fluid. A total of 34 cases were histologically positive for malignancy. All these cases showed strong membranous and cytoplasmic positivity for EMA. Most of cases also showed 2%-5% positivity for CAL. There were 38 cases categorized as atypical or reactive mesothelial cell hyperplasia. These cases showed nuclear and cytoplasmic staining for calretinin and none of these were positive for EMA, although 5 cases showed score 2-3, which was considered as negative.

CONCLUSION

The distinction between reactive and malignant mesothelial cells in cytological specimens can be problematic. A combination of CAL and EMA may help in accurate diagnosis.

Truncation and Mutation of a Transferrin Receptor Aptamer Enhances Binding Affinity

Aptamers are proving their utility in a number of applications. However, to be easily functionalized, their structure needs to be simplified. Therefore, we sought to truncate a 50-nucleotide aptamer specific to the transferrin receptor to its smallest functional unit using rational engineering of the predicted two-dimensional structure of the longer parent sequence. In addition, mutations were introduced into the binding loop to determine their effect on the selectivity of the aptamers. These base mutations enhanced the binding affinity of the aptamer, while retaining its specificity. The equilibrium dissociation constant (Kd) was reduced sixfold following the substitution of all four bases in the binding region. In addition, these aptamers were efficiently internalized into transferrin receptor-positive cells in a similar manner to the transferrin receptor antibody and demonstrated colocalization with this antibody. This study has shown that the smallest functional unit of this aptamer was 14 nucleotides. This small size will be advantageous for future applications, such as drug delivery or functionalization of other therapeutic modalities.

Concordance of Expert Consultation Diagnoses in the Review of Pelvic Washing Specimens

OBJECTIVES

Cytologic specimens are routinely collected as part of gynecologic oncology surgery. Consultation cases often include cytology specimens. Outside diagnosis was compared to consultation diagnosis for cytopathology specimens that were part of larger oncologic cases.

STUDY DESIGN

Gynecologic pathology consultation cases containing pelvic washing (PW) material were queried. Cases had major discordance if the diagnosis changed from negative to positive or vice versa, and minor discordance if an atypical diagnosis was changed to positive or negative or vice versa.

RESULTS

Of 237 cases, 9 showed major discordance (4%), 29 showed minor discordance (12%) and the remaining 199 no discordance (84%). The 9 major discordance cases involved PWs from cases that were performed for ovarian pathology. Treatment would have changed in only 2 of the cases with major discordance. Of the minor discordance cases, 21/29 (72%) involved PW from ovarian cases and 8/29 (28%) were PW from uterine cases.

CONCLUSIONS

Only a few cases showed major or minor discordance, and of those that were discordant, most involved ovarian specimens. Major discordance between original and consulting diagnoses would have changed treatment in only 2 cases.

Cytologic and Immunophenotypic Features of Malignant Cells in Pediatric Body Fluids

OBJECTIVE

Cytospin preparations and immunocytochemistry are common methods in hospitals to evaluate malignancies in body fluids. Characteristics of malignant cells in pediatric body fluids have not been adequately evaluated.

STUDY DESIGN

183 pleural, peritoneal and pericardial pediatric fluid specimens were examined by cytospin preparations and immunocytochemistry from two hospitals using similar procedural techniques. Cytologic diagnoses were correlated with the results of clinical history, histology and ancillary studies.

RESULTS

Forty cases with malignancy were identified (21.9%); the most common diagnoses were rhabdomyosarcoma and acute lymphoblastic lymphoma (9 and 8 cases, respectively). Small round cell tumors revealed similar morphology as clusters of small round cells with central nuclei and scant cytoplasm with frequent small vacuoles. Twenty-one cases were evaluated by immunocytochemistry, 12 by flow cytometry and 5 by cytogenetic analysis. CD3, CD20, TdT, CD10, desmin and myogenin were the most common markers. Staining artifacts causing interpretation difficulties were noted in 5 cases that were resolved by molecular studies and deferral for surgical specimens.

CONCLUSIONS

Small round cell tumors are the most common malignancies encountered in pediatric body fluids and share a nonspecific morphology. Although immunocytochemistry is helpful to arrive at the correct diagnosis, other ancillary studies may be necessary, particularly in hematologic malignancies and other difficult cases.

Diagnostic accuracy of Ber-EP4 for metastatic adenocarcinoma in serous effusions: a meta-analysis

Numerous studies have investigated the utility of Ber-EP4 in differentiating metastatic adenocarcinoma (MAC) from malignant epithelial mesothelioma (MM) and/or reactive mesothelial cells (RM) in serous effusions. However, the results remain controversial. The aim of this study is to determine the overall accuracy of Ber-EP4 in serous effusions for MAC through a meta-analysis of published studies. Publications addressing the accuracy of Ber-EP4 in the diagnosis of MAC were selected from the Pubmed, Embase and Cochrane Library. Data from selected studies were pooled to yield summary sensitivity, specificity, positive and negative likelihood ratio (LR), diagnostic odds ratio (DOR), and receiver operating characteristic (SROC) curve. Statistical analysis was performed by Meta-Disc 1.4 and STATA 12.0 softwares. 29 studies, based on 2646 patients, met the inclusion criteria and the summary estimating for Ber-EP4 in the diagnosis of MAC were: sensitivity 0.8 (95% CI: 0.78-0.82), specificity 0.94 (95% CI: 0.93-0.96), positive likelihood ratio (PLR) 12.72 (95% CI: 8.66-18.7), negative likelihood ratio (NLR) 0.18 (95% CI: 0.12-0.26) and diagnostic odds ratio 95.05 (95% CI: 57.26-157.77). The SROC curve indicated that the maximum joint sensitivity and specificity (Q-value) was 0.91; the area under the curve was 0.96. Our findings suggest that BER-EP4 may be a useful diagnostic adjunctive tool for confirming MAC in serous effusions.

Cell blocks in cytopathology: a review of preparative methods, utility in diagnosis and role in ancillary studies

The cell block (CB) is a routine procedure in cytopathology that has gained importance because of its pivotal role in diagnosis and ancillary studies. There is no precise review in the published literature that deals with the various methods of preparation of CB, its utility in diagnosis, immunocytochemistry (ICC) or molecular testing, and its drawbacks. An extensive literature search on CB in cytology using internet search engines was performed for this review employing the following keywords: cell block, cytoblock, cytology, cytopathology, methods, preparation, fixatives, diagnostic yield, ancillary and molecular studies. Ever since its introduction more than a century ago, the CB technique has undergone numerous modifications to improve the quality of the procedure; however, the overall principle remains the same in each method. CBs can be prepared from virtually all varieties of cytological samples. In today's era of personalized medicine, cytological specimens, including CBs, augment the utility of cytological samples in analysing the molecular alterations as effectively as surgical biopsies or resection specimens. With the availability of molecular targeted therapy for many cancers, a large number of recent studies have used cytological material or CBs for molecular characterization. The various techniques of CB preparation with different fixatives, their advantages and limitations, and issues of diagnostic yield are discussed in this review.

Authors attain comparable or slightly higher rates of citation publishing in an open access journal (CytoJournal) compared to traditional cytopathology journals - A five year (2007-2011) experience

BACKGROUND

The era of Open Access (OA) publication, a platform which serves to better disseminate scientific knowledge, is upon us, as more OA journals are in existence than ever before. The idea that peer-reviewed OA publication leads to higher rates of citation has been put forth and shown to be true in several publications. This is a significant benefit to authors and is in addition to another relatively less obvious but highly critical component of the OA charter, i.e. retention of the copyright by the authors in the public domain. In this study, we analyzed the citation rates of OA and traditional non-OA publications specifically for authors in the field of cytopathology.

DESIGN

We compared the citation patterns for authors who had published in both OA and traditional non-OA peer-reviewed, scientific, cytopathology journals. Citations in an OA publication (CytoJournal) were analyzed comparatively with traditional non-OA cytopathology journals (Acta Cytologica, Cancer Cytopathology, Cytopathology, and Diagnostic Cytopathology) using the data from web of science citation analysis site (based on which the impact factors (IF) are calculated). After comparing citations per publication, as well as a time adjusted citation quotient (which takes into account the time since publication), we also analyzed the statistics after excluding the data for meeting abstracts.

RESULTS

Total 28 authors published 314 publications as articles and meeting abstracts (25 authors after excluding the abstracts). The rate of citation and time adjusted citation quotient were higher for OA in the group where abstracts were included (P < 0.05 for both). The rates were also slightly higher for OA than non-OA when the meeting abstracts were excluded, but the difference was statistically insignificant (P = 0.57 and P = 0.45).

CONCLUSION

We observed that for the same author, the publications in the OA journal attained a higher rate of citation than the publications in the traditional non-OA journals in the field of cytopathology over a 5 year period (2007-2011). However, this increase was statistically insignificant if the meeting abstracts were excluded from the analysis. Overall, the rates of citation for OA and non-OA were slightly higher to comparable.

The use of sensitive chemical antibodies for diagnosis: detection of low levels of EpCAM in breast cancer

EpCAM is expressed at low levels in a variety of normal human epithelial tissues, but is overexpressed in 70–90% of carcinomas. From a clinico-pathological point of view, this has both prognostic and therapeutic significance. EpCAM was first suggested as a therapeutic target for the treatment of epithelial cancers in the 1990s. However, following several immunotherapy trials, the results have been mixed. It has been suggested that this is due, at least in part, to an unknown level of EpCAM expression in the tumors being targeted. Thus, selection of patients who would benefit from EpCAM immunotherapy by determining EpCAM status in the tumor biopsies is currently undergoing vigorous evaluation. However, current EpCAM antibodies are not robust enough to be able to detect EpCAM expression in all pathological tissues. Here we report a newly developed EpCAM RNA aptamer, also known as a chemical antibody, which is not only specific but also more sensitive than current antibodies for the detection of EpCAM in formalin-fixed paraffin-embedded primary breast cancers. This new aptamer, together with our previously described aptamer, showed no non-specific staining or cross-reactivity with tissues that do not express EpCAM. They were able to reliably detect target proteins in breast cancer xenograft where an anti-EpCAM antibody (323/A3) showed limited or no reactivity. Our results demonstrated a more robust detection of EpCAM using RNA aptamers over antibodies in clinical samples with chromogenic staining. This shows the potential of aptamers in the future of histopathological diagnosis and as a tool to guide targeted immunotherapy.

Thank you reviewers – CytoJournal 2011

CytoJournal, with its continued contribution of scientific cytopathology literature to the public domain under open access (OA) charter, thanks its dedicated peer reviewers for devoting significant efforts, time, and resources during 2011. The abstracts of poster-platform submissions to the 59^th Annual Scientific Meeting (November 2011) of the American Society of Cytopathology (ASC) in Baltimore, MD, USA, were peer reviewed by the ASC Scientific Program Committee.