Utilization of ancillary studies in the cytologic diagnosis of respiratory lesions: The papanicolaou society of cytopathology consensus recommendations for respiratory cytology

Molecular Methods: Clinical Utilization and Designing a Test Menu

Pre-analytical factors in molecular oncology diagnostics are reviewed. Issues around sample collection, storage, and transport that might affect the stability of nucleic acids and the ability to perform molecular testing are addressed. In addition, molecular methods used commonly in clinical diagnostic laboratories, including newer technologies such as next-generation sequencing and digital droplet polymerase chain reaction, as well as their applications, are reviewed. Finally, we discuss considerations in designing a molecular test menu to deliver accurate and timely results in an efficient and cost-effective manner.

Risk of malignancy assessment of the different cytologic categories in respiratory cytology samples according to the new guidelines of the Papanicolaou Society of Cytopathology

BACKGROUND

Cytology is extremely important for diagnosis of lung carcinoma and the Papanicolaou Society of Cytopathology (PSC) had proposed a new classification system for respiratory cytology for better communication between physicians and better patient management. The objective of this study is to analyze our samples in accordance with this classification and to evaluate the diagnostic accuracy of various cytologic techniques and to assess the risk of malignancy.

METHODS

Eight hundred and twenty respiratory cytology specimens (FNA, BAL, washing, brushing, sputum) collected between 2019 and 2022 were classified according to the PSC system and the risk of malignancy was assessed for each category using follow-up surgical samples. Sensitivity, specificity, and accuracy rates were determined based on a categorial approach, according to a similar study.

RESULTS

The data of 820 respiratory cytology specimens from 576 patients were analyzed. 2.6% of these were non-diagnostic, 64.1% were NM, 5% were AC, 0.4% were N-B-LG, 4% were SM and 23.9% were ML. The risk of malignancy for each diagnostic category were: 42.8% for non-diagnostic, 31.2% for NM, 43.9% for AC, 87.9% for SM, 94.3% for ML. Sensitivity and specificity was calculated using only the malignant cases considered as positive tests and was 45.57% and 97.34% respectively.

CONCLUSION

Our results correlated with the PSC system, and it was considered useful in clinical practice. However, more studies should be performed to evaluate the usefulness of this system. The ROMs of each category and the impact of different techniques should be further studied.

PD-L1 (22C3) Expression Correlates with Clinical and Molecular Features of Lung Adenocarcinomas in Cytological Samples

INTRODUCTION

PD-L1 expression is the most widely used predictive marker for immune checkpoint inhibitor (ICI) therapy in patients with lung adenocarcinoma. However, the current understanding of the association between PD-L1 expression and treatment response is suboptimal. A significant percentage of patients have only a cytological specimen available for clinical management. Therefore, it is relevant to examine the impact of molecular features on PD-L1 expression in cytological samples and how it might correlate with a therapeutic response.

METHODS

We evaluated patients diagnosed with adenocarcinoma of the lung who had both in-house targeted next-generation sequencing analysis and paired PD-L1 (22C3) immunohistochemical staining performed on the same cell blocks. We explored the association between molecular features and PD-L1 expression. In patients who underwent ICIs therapy, we assessed how a specific gene mutation impacted a therapeutic response.

RESULTS

145 patients with lung adenocarcinoma were included in this study. PD-L1-high expression was found to be more common in pleural fluid than in other sample sites. Regional lymph node samples showed a higher proportion of PD-L1-high expression (29%) compared with lung samples (6%). The predictive value of PD-L1 expression was retained in cytological samples. Mutations in KRAS were also associated with a PD-L1-high expression. However, tumors with TP53 or KRAS mutations showed a lower therapy response rate regardless of the PD-L1 expression.

CONCLUSION

Cytological samples maintain a predictive value for PD-L1 expression in patients with lung adenocarcinoma as regards the benefit of ICI treatment. Specific molecular alterations additionally impact PD-L1 expression and its predictive value.

Quality of cell blocks prepared from residual pleural effusion and bronchial washing samples for immunocytochemistry

INTRODUCTION

Cell blocks (CBs) enable the long-term preservation of cytological samples. The aim of this study was to analyse the quality of CBs prepared from leftover fluid from lung adenocarcinoma pleural effusion samples and residual bronchial washing sediment for immunocytochemistry.

METHODS

The residual part of 455 lung adenocarcinoma pleural effusion samples and sediment from 384 bronchial washing samples were used to prepare CBs following the agarose method. The quality of CBs was evaluated based on the quantity of malignant cells in haematoxylin and eosin-stained slides and interpreted as optimal or insufficient for immunocytochemistry. Immunocytochemistry on CBs was performed using the Dako EnVision™ FLEX detection visualisation system. The CB results for TTF-1, ALK, and PD-L1 immunocytochemistry were compared with the corresponding cytological smears.

RESULTS

Among all CBs, 202 (44.4%) from leftover pleural effusion fluid and 85 (22.1%) from residual bronchial washing sediment had an optimal number of lung adenocarcinoma cells. Eight pleural effusion CBs were stained for TTF-1. Four pleural effusion and two bronchial washing CBs were stained for ALK and PD-L1. All tested pleural effusion CBs were confirmed positive for TTF-1 and negative for ALK. The PD-L1 tumour proportion score (TPS) was ≥ 50% in two pleural effusions. ALK was confirmed negative in bronchial washing CBs. One bronchial washing CB was interpreted as PD-L1-negative while the corresponding smear was positive (TPS ≥1%; 2%).

CONCLUSION

The CB results of TTF-1, ALK, and PD-L1 corresponded to the findings for the smears. The inclusion of CBs prepared from leftover fluid from pleural effusion samples and residual bronchial washing sediment in routine cytological practice could provide a source of high-quality material for immunocytochemistry in addition to smears and cytospins.

PD-L1 immunohistochemical testing: A review with reference to cytology specimens

BACKGROUND

Immunotherapy based on disruption of the PD-1/PD-L1 axis is standard of care for many high stage malignancies including melanomas, non-small cell carcinomas of the lung, triple negative breast carcinomas, and squamous cell carcinomas of the head and neck. Eligibility for immunotherapy requires immunohistochemical assessment of PD-L1 expression. Currently, many high stage malignancies are diagnosed by cytology and cytologic material is the only specimen available for ancillary testing. Formal guidelines do not currently exist defining the optimal specimen type, antibody to be used or the best scoring system for cytologic material. Significant information has been published for PD-L1 testing of pulmonary specimens but much less data exists for the reproducibility, accuracy and best practices for material obtained from other body sites and types of malignancy.

METHODS

We searched the PubMed data base for manuscripts relating to PD-L1 testing of cytologic specimens. The search period was between 2016 and 2022. The search terms used were PD-L1, cytology, FNA, immunotherapy, immunohistochemistry, immunocytochemistry, cytology-histology correlation. Cross referencing techniques were used to screen for the most relevant manuscripts. The abstracts of these were then reviewed for final data collection and analysis.

RESULTS

A total of 86 studies were identified conforming to study relevancy. These were reviewed in their entirety by two authors (LJL, TZ) for extraction of data. The majority of studies involved pulmonary specimens (79) with three relating to PD-L1 testing of head and neck cytologic specimens and one each for PD-L1 testing of cytology specimens from melanomas, pancreas, pleural fluids, and triple negative breast carcinomas. While smears could be used, most studies found cell blocks optimal for testing.

SUMMARY

Currently, four drugs are approved for immunotherapy based on PD-L1 status. These drugs require specific antibody clones as well as scoring systems. Scoring systems and cut points vary with the type of neoplasm being treated. Cytology specimens from the lung, head and neck and melanomas can all be used for PD-L1 testing with good agreement with corresponding histology specimens.

Recommendations for optimizing the use of cytology in the diagnosis and management of patients with lung cancer

Non-small cell lung cancer (NSCLC) is one of the oncological entities with the greatest evolution in molecular diagnosis due to the large number of diagnostic biomarkers and new treatments approved by international regulatory agencies. An accurate, early diagnosis using the least amount of tissue is the goal for the establishing and developing precision medicine for these patients. Rapid on-site evaluation (ROSE) provides cytological samples of optimal quantity and quality for a complete diagnosis of NSCLC. The usefulness of cytological samples has been demonstrated, not only for massive parallel sequencing but also for the quantification of the expression of programmed death-ligand 1 (PD-L1) and tumour mutational burden (TMB). Pre-analytical, analytical, and post-analytical recommendations are made for the management and appropriate use of cytological samples in order to obtain all the information necessary for the diagnosis and treatment of patients with NSCLC according to current quality parameters.

Approach to Mediastinal Fine Needle Aspiration Cytology

Mediastinal fine needle aspirations are routinely encountered in cytopathology practice. Mediastinal lesions may pose diagnostic challenges owing to their rarity and locations associated with the complexity of the mediastinal anatomic structures in the thoracic cavity. Diagnosing mediastinal lesions and guiding patient management usually require correlating with clinical and radiologic findings, being familiar with cytomorphologic features and appropriately triaging the diagnostic material for ancillary testing. This review proposes a practical approach to interpret mediastinal fine needle aspirations and emphasizes potential diagnostic pitfalls for mediastinal lesions including benign cysts, thymic neoplasms, lymphoproliferative disorders, germ cell tumors, mesenchymal tumors, and metastatic tumors.

Conformity of Fine Needle Aspiration Biopsy (FNAB) and Core Needle Biopsy (CNB) in peripheral lung tumor patients: A cross-sectional study

Background

The problem of establishing lung tumor diagnostics is a challenge for clinicians, especially pulmonologists, in determining a definitive diagnosis of a lung tumor.

Objective

Analyzing the conformity of anatomical pathology results between fine-needle aspiration biopsy (FNAB) and core needle biopsy (CNB) materials in peripheral lung tumors.

Methods

A cross-sectional study was conducted from July 2019 to December 2020 with 66 participants. Participants were examined for CNB and FNAB, in which the results of these examinations were compared for conformity. Statistical analysis used the Kappa test with p < 0.05.

Result

Most participants' tumor size was >70 mm, with FNAB results showing malignant category (39.5%), non-malignant (40.0%), and undiagnosed (38.9%; p = 0.757). Meanwhile, CNB examination showed a tumor size of >70 mm that was categorized into malignant (40.4%) and non-malignant (33.3%; p = 0.510). Most tumors were located in the right superior lobe that had FNAB results in the malignant (39.5%), non-malignant (30.0%) and undiagnosed (27.8%; p = 0.306) categories. The CNB examination also showed that most tumors were located in the right superior lobe, which had resulted in the category of malignant (34.4%), non-malignant (26.7%), and undiagnosed (75.0%; p = 0.240). Conformity of anatomical pathology results from FNAB and CNB subject such as malignancy category of 35 participants (74.5%), non-malignancy of 7 participants (53.8%) and undiagnosed of 4 participants (16.7%) with an accuracy of 69.69% (Κ = 0.43; p = 0.001).

Conclusion

There is a conformity between the anatomical pathology results from FNAB and CNB materials for the diagnosis of lung tumors. CNB showed better results in the detection of anatomical malignancy and specimen adequacy.

•

There is a conformity between the results of FNAB and CNB assisted by ultrasound.

•

FNAB and CNB results in lung cancer are similar >70%.

•

The use of FNAB followed by CNB minimizes misdiagnosis.

Crown-Cut Endobronchial Ultrasound Guided Transbronchial Aspiration Needle: First Real-World Experiences

Advancements in personalized medicine have increased the demand for quantity and preservation of tissue architecture of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples. These demands may be addressed by the SonoTip TopGain^® needle, which has a 3-point crown-cut design that contrasts with the standard single bevel design of the ViziShot 2^®. The objective was to compare the SonoTip TopGain^® and ViziShot 2^® needles by considering biopsy sample characteristics, diagnostic accuracy, and patient safety. The primary endpoint of the study was the number of high-power fields (HPFs) in the center of the formalin-fixed paraffin-embedded cell block per sample. The lymph node with the highest probability for malignant infiltration based on size and sonographic appearance was chosen as the target lymph node for 20 patients. The same lymph node in each patient was sampled using both the ViziShot 2^® and SonoTip TopGain^® needles. The samples were measured, sliced, and analyzed by a pathologist. Sixteen patients were biopsied with both needles. Four patients could not be biopsied with the SonoTip TopGain^® needle since it could not penetrate cartilage or be repositioned to bypass cartilage. HPFs and sample dimensions were significantly greater in the patients where sampling with the SonoTip TopGain^® needle was possible (p = 0.007 and p = 0.005, respectively). Diagnostic accuracy and safety profiles were comparable. Significantly more material can be sampled using the SonoTip TopGain^® needle when cartilage penetration can be avoided. This improves the yield for molecular workup in the era of personalized medicine.

Technical aspects of the use of cytopathological specimens for diagnosis and predictive testing in malignant epithelial neoplasms of the lung

Lung cancer is a leading cause of cancer mortality worldwide but recent years have seen a rapidly rising proportion of cases of advanced non-small cell carcinoma amenable to increasingly targeted therapy, initially based on the differential response to systemic treatment of tumours of squamous or glandular differentiation. In two-thirds of the cases, where patients present with advanced disease, both primary pathological diagnosis and biomarker testing is based on small biopsies and cytopathological specimens. The framework of this article is an overview of the technical aspect of each stage of the specimen pathway with emphasis on maximising potential for success when using small cytology samples. It brings together the current literature addressing pre-analytical and analytical aspects of specimen acquisition, performing rapid onsite evaluation, and undertaking diagnostic and predictive testing using immunocytochemistry and molecular platforms. The advantages and drawbacks of performing analysis on cell block and non-cell block specimen preparations is discussed.

Challenges in Pathology Specimen Processing in the New Era of Precision Medicine

CONTEXT.—

Precision therapies for patients with driver mutations can offer deep and durable responses that correlate with diagnosis, metastasis prognosis, and improvement in survival. Such targeted therapies will continue to increase, pushing us to change our traditional approaches. We needed to search for new tools to effectively integrate technological advancements into our practices because of their capability to improve the efficiency and accuracy of our diagnostic and treatment approaches. Perhaps nothing is as relevant as identifying and implementing new workflows for processing pathologic specimens and for improving communication of critical laboratory information to and from clinicians for appropriate care of patients in an efficient and timely manner.

OBJECTIVES.—

To define the gold standard in delivering the best care for patients, to identify gaps in the process, and to identify potential solutions that would improve our process, including gaps related to knowledge, skills, attitudes, and practices.

DESIGN.—

We assembled a team across disciplines to systematically perform a gap analysis study to clarify the discrepancy between the current reality in pathology specimen processing and the desired optimal situation to deliver the results intended for patient care.

RESULTS.—

A practical collaborative workflow for specimen management seeking the cooperation of the stakeholders in each medical discipline to provide guidelines in specimen collection, delivery, processing, and reporting of results with the ultimate goal of improving patients' outcomes is provided.

CONCLUSIONS.—

New tools are required to effectively integrate data-driven approaches in specimen processing to meet the new demands.

Diagnostic Challenges in Fine-Needle Aspiration Cytology of Mediastinal Tumors and Lesions

CONTEXT.—

Mediastinal tumors/lesions are frequently encountered in daily cytopathology practice. These lesions are accessible through endoscopic/endobronchial ultrasound-guided or computed tomography-guided fine-needle aspiration cytology and represent a wide range of primary and metastatic tumors. This often poses diagnostic challenges because of the complexity of the mediastinal anatomic structures. Tumors metastatic to mediastinal lymph nodes represent the most common mediastinal lesions and must be differentiated from primary lesions.

OBJECTIVE.—

To provide an updated review on the fine-needle aspiration cytology of mediastinal tumors/lesions, with an emphasis on diagnostic challenges. This review encompasses thymic epithelial neoplasms, mediastinal lymphoproliferative disorders, germ cell tumors, neuroendocrine tumors, soft tissue tumors, and metastatic tumors. Differential diagnoses; useful ancillary studies, including targeted immunohistochemical panels; and diagnostic pitfalls are discussed.

DATA SOURCES.—

Data were gathered from a PubMed search of peer-reviewed literature on mediastinal tumors. Data were also collected from the authors' own practices.

CONCLUSIONS.—

Fine-needle aspiration cytology plays a vital role in evaluation of mediastinal lesions. Being familiar with the clinical and cytomorphologic features of these lesions, appropriately triaging the diagnostic material for ancillary testing, and correlating with radiologic findings are important in arriving at correct diagnoses and guiding management.

Molecular Methods: Clinical Utilization and Designing a Test Menu

Pre-analytical factors in molecular oncology diagnostics are reviewed. Issues around sample collection, storage, and transport that might affect the stability of nucleic acids and the ability to perform molecular testing are addressed. In addition, molecular methods used commonly in clinical diagnostic laboratories, including newer technologies such as next-generation sequencing and digital droplet polymerase chain reaction, as well as their applications, are reviewed. Finally, we discuss considerations in designing a molecular test menu to deliver accurate and timely results in an efficient and cost-effective manner.

PD-L1 in Cytological Samples: A Review and a Practical Approach

With a growing number of predictive biomarkers needed to manage patients with non-small cell lung cancer (NSCLC), there has been a paradigm shift in care and handling of diagnostic samples. Among the various testing methods, immunohistochemistry (IHC) is the most cost- effective and widely available. Furthermore, over the past decade immunotherapy has emerged as one of the most promising cancer treatments. In this scenario IHC is the most used testing method available for PDL-1/PD1 immunotherapy. Several monoclonal antibodies targeting programmed death 1 (PD-1)/programmed death ligand-1 (PD-L1) pathways have been integrated into standard-of-care treatments of a wide range of cancer types, once provided evidence of PD-L1 expression in tumor cells by immunohistochemistry (IHC). Since currently available PD-L1 assays have been developed on formalin-fixed paraffin embedded (FFPE) histological specimens, a growing body of research is being dedicated to confirm the feasibility of applying PDL-1 assays also to cytological samples. Albeit promising results have been reported, several important issues still need to be addressed. Among these are the type of cytological samples, pre-analytical issues, cyto-histological correlation, and inter-observer agreement. This review briefly summarizes the knowledge of the role of cytopathology in the analysis of PD-L1 by immunocytochemistry (ICC) and future directions of cytopathology in the immunotherapy setting.

Testing EGFR with Idylla on Cytological Specimens of Lung Cancer: A Review

The current standard of care for advanced non-small-cell lung cancer is based on detecting actionable mutations that can benefit from targeted therapy. Comprehensive genetic tests can have long turn-around times, and because EGFR mutations are the most prevalent actionable mutation, a quick detection would enable a prompt initiation of targeted therapy. Furthermore, the scarcity of diagnostic material means that sometimes only cytologic material is available. The Idylla™ EGFR assay is a real-time PCR–based method able to detect 51 EGFR mutations in 2.5 h. Idylla is validated for use only on FFPE sections, but some researchers described their experiences with cytological material. We reviewed the relevant literature, finding four articles describing 471 cases and many types of cytological input material: smears, cell-block sections, suspensions, and extracted DNA. The sensitivity, specificity, and limit of detection appear comparable to those obtained with histological input material, with one exception: the usage of scraped stained smears as input may reduce the accuracy of the test. In conclusion, usage of cytological material as input to the Idylla EGFR test is possible. A workflow where common mutations are tested first and fast, leaving rarer mutations for subsequent comprehensive profiling, seems the most effective approach.

Digital/Computational Technology for Molecular Cytology Testing: A Short Technical Note with Literature Review

This short article describes the method of digital cytopathology using Z-stack scanning with or without extended focusing. This technology is suitable to observe such thick clusters as adenocarcinoma on cytologic specimens. Artificial intelligence (AI) has been applied to histological images, but its application on cytologic images is still limited. This article describes our attempt to apply AI technology to cytologic digital images. For molecular analysis, cytologic materials, such as smear, LBC, and cell blocks, have been successfully used for targeted single gene detection and multiplex gene analysis with next-generation sequencing. As a future perspective, the system can be connected to full automation by combining digital cytopathology with AI application to detect target cancer cells and to perform molecular analysis. The literature review is updated according to the subjects.

Cytology samples and molecular biomarker testing in lung cancer-advantages and challenges

This review presents an overview on molecular diagnostic in lung cancer using cytologic samples. Every patient with advanced non-small cell lung cancer (NSCLC) should be tested for targetable driver mutations and gene arrangements. If a mutation is found, this may open an option for targeted therapy. As most of the NSCLC patients in advanced stage of disease are no candidates for surgery, these tests have to be performed on small biopsies or cytology samples. The most common and treatable gene alterations should be tested in every patient: EGFR, ALK, ROS1. A growing number of other genetic changes with targetable mutations may become treatable in the near future. To find patients who might profit from inclusion into clinical studies, relevant additional markers may be tested in an appropriate context. Another important approach for treatment is immunotherapy of lung cancer, which is guided by status of PD-L1 expression on tumour cells. The use of cytology samples carries considerable advantages: often, DNA of high quality is extracted thus enabling easy and precise analysis, and samples may be easily obtained. In case of effusions, effusion fluid seldom is not aspirated for immediate patient relief, so no additional dedicated procedure is needed. Some challenges exist: If the tumour cell count is low, mutations with a low allelic frequency may be missed. In cellblocks formalin-induced DNA, damage may obviate any DNA analysis. In very cellular smears, FISH may be impossible due to massive overlapping of nuclei. Autofluorescence may impede FISH analysis. Although there is no real universal test for genomic profiling for lung cancer, the pathology laboratory must be prepared to offer different assays on different specimens in order to address turnaround time and optimise detections of difficult tumour alterations such as gene fusions. The data from the literature demonstrate that cytology show consistent results, and it is a good alternative for lung cancer molecular testing.

Combining biopsy tools improves mutation detection rate in central lung cancer

Molecular genetic testing (such as next-generation sequencing (NGS)) and programmed death ligand 1 (PD-L1) staining have become essential for the evaluation of lung cancer tissue [1, 2]. Endobronchial forceps biopsy (FB) is considered the gold standard for tissue sampling in central lung cancer [3].

In central exophytic lung cancer, the detection rate of oncogenic mutations and PDL1 positivity may be increased by combined sampling by forceps and EBUS-TBNA. The additional sampling of mediastinal lymph node and ctDNA may not be of additional benefit.https://bit.ly/2Ve41EF

Use of cytology centrifuged supernatants improves cost and turnaround time for targeted next generation sequencing

BACKGROUND

Molecular testing is an essential step in providing patients with advanced non-small-cell lung cancer (NSCLC), the most appropriate front-line targeted therapies. We recently implemented targeted NGS on previously discarded cytology centrifuged supernatant (CCS).

METHODS

In this study, we reviewed our implementation process to evaluate its performance. Performance and turnaround time (TAT) of molecular testing on all cytology NSCLC cases submitted for targeted NGS from June 2018 to September 2019 were evaluated, which included 46 and 62 cytology cases before and after implementation of CCS, respectively. Associated cost savings using CCS was also analyzed.

RESULTS

The mean TAT defined as the time of collection to time of reporting was 8.5 ± 1.8 days in CCS cohort (range 5-13) as compared with 12.2 ± 5.3 days in the (FFPE) cell block (CB) cohort (range: 6-27). The success rate of sequencing was similar for both cohorts (100% in CCS and 96% in FFPE CB).

CONCLUSION

Our results demonstrate that NGS using CCS improves TAT, preserves FFPE CB for other testing, and results in cost savings of $50 per case.

Current classification systems and standardized terminology in cytopathology

The history of classification systems and the search for a unified nomenclature in cytopathology spans several decades and expresses the preoccupation of all those involved to make cytopathology a reliable diagnostic tool and a trusted screening method. Early classification schemes, applicable to exfoliative and aspiration cytology, attempted to set some basic standards for how non-gynecological cytopathology findings should be reported. While useful in establishing some basic guidelines, these were not specific to the various fields of non-gynecologic cytopathology, often burdened with specific problems. Cytopathology has evolved tremendously in the last couple of decades, undoubtedly boosted by the emergence of various classification schemes that, more than ever, are based on evidence gathered by professionals across the globe. The benefit of classification systems and standardized nomenclature in cytopathology is to provide useful, clear, and clinically relevant information for clinicians and ultimately to provide the best patient care. Standardized reporting systems make cytopathology reports more meaningful and robust. It now became standard that these include by default elements, such as adequacy criteria, diagnostic groups, risk of malignancy (ROM), and recommendations for patient management. In this brief review, we attempted to summarize how these classification schemes emerged and how they are reshaping the landscape of diagnostic cytopathology.

Immunocytochemistry of cytology specimens for predictive biomarkers in lung cancer

With a growing number of predictive biomarkers that have emerged in non-small cell lung carcinoma (NSCLC), there has been a paradigm shift in the management of these patients. Of the various predictive biomarker testing methods, immunohistochemistry (IHC) is the most widely available, cost-effective, and commonly used methods. However, most predictive IHC assays are validated primarily on formalin-fixed paraffin-embedded (FFPE) histologic tissue samples and translating these assays to cytologic specimens requires additional and rigorous validation. This is part due to the lack of standardized processing protocols in cytology resulting in a variety of preanalytic variables that can impact the antigenicity of antibodies used for predictive biomarker testing. The review article discusses the various preanalytical and analytical factors that impact immunocytochemistry (ICC) in cytologic specimens and summarizes the current published literature on ALK, ROS1, PD-L1, and other predictive biomarker ICC in cytology.

Lung cancer cytology and small biopsy specimens: diagnosis, predictive biomarker testing, acquisition, triage, and management

In the 21st century, there has been a dramatic shift in the management of advanced-stage lung carcinoma, and this has coincided with an increasing use of minimally invasive tissue acquisition methods. Both have had significant downstream effects on cytology and small biopsy specimens. Current treatments require morphologic, immunohistochemical, and/or genotypical subtyping of non-small cell lung carcinoma. To meet these objectives, standardized classification of cytology and small specimen diagnoses, immunohistochemical algorithms, and predictive biomarker testing guidelines have been developed. This review provides an overview of current classification, biomarker testing, methods of small specimen acquisition and triage, clinical management strategies, and emerging technologies.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration for PD-L1 Testing in Non-small Cell Lung Cancer

BACKGROUND

Programmed death-ligand 1 (PD-L1) expression on cancer cells is a clinically important biomarker to select patients with non-small cell lung cancer (NSCLC) for treatment with programmed death-1/PD-L1 inhibitors. Clinical trials of immunotherapy in patients with NSCLC have required histologic evidence for PD-L1 testing; in clinical practice, cytologic samples commonly are acquired in patients with advanced disease.

RESEARCH QUESTION

This study aims to investigate whether endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples are adequate for PD-L1 testing in NSCLC.

STUDY DESIGN AND METHODS

This study investigates the sampling adequacy of EBUS-TBNA for PD-L1 testing when compared with other methods. Furthermore, the relationship between clinicopathologic characteristics and PD-L1 expression in the study population have been examined. Five hundred seventy-seven NSCLC specimens were analyzed from consecutive patients with NSCLC across six centers in the United Kingdom and one center in the United States between January 2015 and December 2016.

RESULTS

In the EBUS-TBNA group (189 specimens), the overall percentage of patients with successful PD-L1 testing was 94.7%. There was no significant difference in sampling adequacy with other methods of tissue acquisition. Older patients had higher failure rates of PD-L1 testing (OR, 1.06; P = .008). In multivariate analysis, advanced N-stage (P = .048) and presence of brain metastasis (P < .001) were associated with high PD-L1 expression.

INTERPRETATION

This large multicenter study shows that EBUS-TBNA provides samples adequate for PD-L1 testing and that advanced N stage and the presence of brain metastasis are associated with high PD-L1 expression.

Evolution of guidelines for respiratory cytology by the Papanicolaou Society of Cytopathology

Cytology serves a fundamental role in the evaluation of the lower respiratory tract. Cytological specimens are often the first diagnostic attempt for the evaluation of radiographic alterations. The categorization of the pathological process as infectious, inflammatory or neoplastic is critical in guiding further clinical management of the affected patient. Therefore it is imperative that cytopathologists use a standardized approach to sample handling and reporting in order to establish clear communication with the treating physician. The Papanicolaou Society of cytopathology has been an active leader in this field and has proposed several guidelines for sampling, handling, and reporting of lower respiratory tract cytology. These guidelines have been updated to incorporate new emerging concepts and technologies in the field. Respiratory medicine is a fast growing area with constant new challenges, thus requiring an ever demanding adaptation from cytopathologists and cytology specific guidelines.

[Cytology of primary lung cancer]

BACKGROUND

In addition to histological examinations, cytological samples are also being evaluated with increasing frequency for the diagnosis of lung carcinoma.

OBJECTIVES

Possible applications of and techniques for cytological examinations are presented. Typical morphologies of primary lung cancer and metastatic disease are shown.

MATERIAL AND METHODS

Samples were obtained during bronchoscopy, serous effusion fluid, and fine-needle aspiration cytology. Special technical features of the cytological samples are discussed. Cytomorphology of pulmonary adenocarcinoma, squamous-cell carcinoma, and small-cell lung carcinoma are shown.

RESULTS

There are clear-cut diagnostic criteria for the main subtypes of primary lung carcinoma.

CONCLUSIONS

Cytological examination is a valuable addition to histology for lung carcinoma diagnostics.

Australian consensus statement for best practice ROS1 testing in advanced non-small cell lung cancer

Lung cancer is the most commonly diagnosed malignancy and the leading cause of death from cancer globally. Diagnosis of advanced non-small cell lung cancer (NSCLC) is associated with 5-year relative survival of 3.2%. ROS proto-oncogene 1 (ROS1) is an oncogenic driver of NSCLC occurring in up to 2% of cases and commonly associated with younger age and a history of never or light smoking. Results of an early trial with the tyrosine kinase inhibitor (TKI) crizotinib that inhibits tumours that harbour ROS1 rearrangements have shown an objective response rate (ORR) of 72% (95% CI 58-83%), median progression free survival (PFS) of 19.3 months (95% CI 15.2-39.1 months) and median overall survival (OS) of 51.4 months (95% CI 29.3 months to not reached). Therefore, with the availability of highly effective ROS1-targeted TKI therapy, upfront molecular testing for ROS1 status alongside EGFR and ALK testing is recommended for all patients with NSCLC. We review the tissue requirements for ROS1 testing by immunohistochemistry (IHC) and fluorescent in situ hybridisation (FISH) and we present a testing algorithm for advanced NSCLC and consider how the future of pathology testing for ROS1 may evolve.

A practical guide for ancillary studies in pulmonary cytologic specimens

Although most pulmonary cytologic specimens obtained by either exfoliation or fine needle aspirates can be reliably and accurately diagnosed based on pure morphologic criteria alone, a small proportion of cases require ancillary studies for either refining a diagnosis, for resolving a differential diagnosis or increasingly, for predictive purposes in primary lung carcinomas. This article aims to provide practical guidance on the use of common ancillary studies in pulmonary cytologic specimens. Cancer Cytopathol 2018;000:000-000. © 2018 American Cancer Society.

Bronchoscopic Brushing from Central Lung Cancer-Next Generation Sequencing Results are Reliable

The role of bronchoscopic brushing for tumor detection and molecular testing in central lung cancer is unclear. In this study, 50 consecutive subjects with suspected central lung cancer underwent bronchoscopic brushing (31 males, median age 70, 5 never smokers). Histological results were: NSCLC/SCLC/low-grade-NET/granulation tissue in 36/8/2/4 cases. Next generation sequencing (NGS) was feasible in 62% of tumor-positive brush smear samples. In 78% of these cases, NGS displayed identical results compared to histology samples, in 22% NGS from brush smears detected specific mutations, whereas DNA quality from forceps biopsy was insufficient for NGS analysis. Sensitivity, specificity, positive predictive value, negative predictive value of brush smear analysis were 66% (95% confidence interval 50-79), 100% (40-100), 100% (85-100), and 21% (7-46). For the combined analysis of brush smear, brush tip washing and sheath tube content sensitivity was slightly elevated at 69% (53-81). In central lung cancer, bronchoscopic brushing detects tumor cells in about two-third of cases and allows a decision for or against targeted therapy in the majority of tumor-positive cases on the basis of NGS analysis.

Precision cytopathology: expanding opportunities for biomarker testing in cytopathology

Precision cytopathology refers to therapeutically linked biomarker testing in cytopatology, a dynamically growing area of the discipline. This review describes basic steps to expand precision cytopathology services. Focusing exclusively on solid tumors, the review is divided into four sections: Section 1: Overview of precision pathology- opportunities and challenges; Section 2: Basic steps in establishing or expanding a precision cytopathology laboratory; Section 3: Cytopathology specimens suitable for next generation sequencing platforms; and Section 4: Summary. precision cytopathology continues to rapidly evolve in parallel with expanding targeted therapy options. Biomarker assays (companion diagnostics) comprise a multitude of test types including immunohistochemistry, in situ hybridization and molecular genetic tests such as PCR and next generation sequencing all of which are performable on cytology specimens. Best practices for precision cytopathology will incorporate traditional diagnostic approaches allied with careful specimen triage to enable successful biomarker analysis. Beyond triaging, cytopathologists knowledgeable about molecular test options and capabilities have the opportunity to refine diagnoses, prognoses and predictive information thereby assuming a lead role in precision oncology biomarker testing.

Acquired Resistance to Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancers: The Role of Next-Generation Sequencing on Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration Samples

CONTEXT

- Molecular testing is essential for the diagnostic workup of patients with advanced non-small cell lung cancers. Cytology specimens from minimally invasive procedures, such as endobronchial ultrasound-guided transbronchial needle aspiration, are often the only available samples for these patients. The implementation of molecular diagnostic testing, and in particular next-generation sequencing-based testing, on these cytologic specimens is currently an evolving field for lung cytopathology. The application of these molecular analyses on tyrosine kinase inhibitor-resistant non-small cell lung cancers raises unique technical, biologic, and clinical challenges.

OBJECTIVE

- To provide an overview of the implementation of next-generation sequencing analysis on endobronchial ultrasound-guided transbronchial needle aspiration samples to detect the molecular aberrations underneath the phenomenon of acquired resistance in patients with non-small cell lung cancers progressing while on the EGFR/ALK tyrosine kinase inhibitor treatment.

DATA SOURCES

- Peer-reviewed original articles, review articles, and published guidelines and expert opinion reports were reviewed, together with our single-center experience.

CONCLUSIONS

- Next-generation sequencing analyses and the endobronchial ultrasound-guided transbronchial needle aspiration procedure may represent a valuable strategy to address the unique requirements of molecular testing on tyrosine kinase inhibitor-resistant non-small cell lung cancers.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration: Techniques and Challenges

Intrathoracic lymphadenopathy is a common problem encountered in clinical practice and is caused by a wide variety of diseases. Traditionally, the mediastinal lymph nodes were sampled using conventional transbronchial needle aspiration (TBNA), or surgical methods such as mediastinoscopy, and thoracotomy (open or video-assisted thoracoscopy). However, surgical modalities including mediastinoscopy are invasive, expensive, and not universally available. Moreover, they are associated with considerable morbidity and mortality. Conventional TBNA although minimally invasive has a low diagnostic yield. In the last decade, endobronchial ultrasound-guided TBNA (EBUS-TBNA) has emerged as the diagnostic procedure of choice in evaluating undiagnosed intrathoracic lymphadenopathy. EBUS-TBNA is also currently the preferred modality in the mediastinal staging of lung cancer. The procedure is minimally invasive, safe, and can be performed as a day-care procedure. In the era of personalized medicine in lung cancer, optimizing the procedure, sample collection, and processing are crucial, as more tissue is required for performing a wide array of molecular tests. Despite its widespread use and acceptance, the diagnostic sensitivity of EBUS-TBNA is still low. To maximize the yield, cytologists and physicians should be aware of the technical details of the procedure. Herein, we discuss the technique of performing EBUS-TBNA, its indications, contraindications, and the processing of the samples at our bronchoscopy suite. We also highlight the challenges faced by the cytologists and clinicians while processing EBUS aspirates.

Molecular Testing Strategies for Pulmonary Adenocarcinoma: An Optimal Approach With Cost Analysis

CONTEXT.—

Molecular analysis of lung adenocarcinoma for therapeutically important genes is standard of practice, with multiple professional organizations recommending testing of all adenocarcinomas for mutations in EGFR, ALK, and ROS1. Some organizations recommend analyzing these genes in association with a panel. Few data exist as to optimal testing method or optimal sequence of testing from a cost perspective.

OBJECTIVE.—

To determine which order of gene testing was least costly and whether sequential, small panel, or next-generation sequencing (NGS) was cheapest.

DESIGN.—

Recent recommendations propose a set of essential molecular tests (EGFR, ALK, and ROS1) and an optional set of molecular tests that may be useful for selection of clinical trials. We compared the costs of different testing sequencing strategies for both the 3 essential genes and for 5 optimal genes. Testing costs were determined by a survey of prices from large laboratories. The strategy most frequently rated as the lowest cost strategy was designated the optimal testing strategy.

RESULTS.—

Sequential testing of the essential genes in the order EGFR-ROS1-ALK was optimal from a cost perspective. The expected cost of sequential testing was $2227 (95% CI, $1733-$2794). The cost of NGS was $2500. The expected cost per positive result was $11,362 using this strategy.

CONCLUSIONS.—

Molecular testing of lung adenocarcinomas for the set of 3 essential genes and 5 optional genes can be performed by a variety of methods and in a variety of sequences. From a cost perspective, sequential testing in the order EGFR, ROS1, then ALK is optimal. NGS would be competitive if the price was less than $2200. NGS is optimal if testing for the 3 essential genes will be followed by testing for the 5 optional genes. NGS testing is optimal if the clinician plans to test both essential and optional genes.

Diagnostic Accuracy of Fine-Needle Aspiration Cytology for Discrimination of Squamous Cell Carcinoma from Adenocarcinoma in Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

To determine the accuracy with which morphology alone can distinguish adenocarcinoma and squamous cell carcinoma in non-small cell lung cancer.

METHODS

We performed a systematic review and meta-analysis. Three data bases (MEDLINE, EMBASE, Scopus) were searched for studies on the diagnostic accuracy of subtyping non-small cell lung cancer. Accuracy data was abstracted and synthesized using bivariate mixed effects logistic regression as implemented in the midas package in Stata 14. Heterogeneity was assessed using the Higgins I2.

RESULTS

We included 17 studies (2,235 cases). Most studies had a low risk of bias. The pooled diagnostic accuracy for cytological diagnosis of adenocarcinoma resulted in a sensitivity of 63% (48-76%) and specificity of 95% (87-98%). The I2 values were 93 and 88% for sensitivity and specificity, respectively. The pooled diagnostic accuracy for the cytological diagnosis of squamous cell carcinoma resulted in a sensitivity of 84% (79-88%) and a specificity of 90% (84-94%). The I2 values were 69 and 86% for sensitivity and specificity, respectively.

CONCLUSION

Accuracy varies widely by study and summary estimates do not provide a useful representation of accuracy. Squamous cell carcinoma was diagnosed more accurately than adenocarcinoma.

Committee II: Guidelines for cytologic sampling techniques of lung and mediastinal lymph nodes

The Papanicolaou Society of Cytopathology has developed a set of guidelines for pulmonary cytology including indications for bronchial brushings, washings, and endobronchial ultrasound guided transbronchial fine-needle aspiration (EBUS-TBNA), technical recommendations for cytological sampling, recommended terminology and classification schemes, recommendations for ancillary testing and recommendations for post-cytological management and follow-up. All recommendations are based on the expertise of the authors, an extensive literature review and feedback from presentations at national and international conferences. This document selectively presents the results of these discussions. The present document summarizes recommendations regarding techniques used to obtain cytological and small histologic specimens from the lung and mediastinal lymph nodes including rapid on-site evaluation (ROSE), and the triage of specimens for immunocytochemical and molecular studies.

Feasibility of endobronchial ultrasound transbronchial needle aspiration for massively parallel next-generation sequencing in thoracic cancer patients

INTRODUCTION

Next-generation sequencing (NGS) allows for the identification of a growing number of therapeutic and prognostic molecular targets. However, NGS typically requires greater quantities of DNA than traditional molecular testing does. Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive procedure used to sample central thoracic lesions, but it is not well established whether this technique provides sufficient material for NGS.

METHODS

We performed a retrospective review of EBUS-TBNA at our institution (3/1/14-9/28/16). NGS was performed using a comprehensive hybrid-capture based assay (MSK-IMPACT) that detects >340 gene mutations. Samples found to be diagnostic for malignancy and for which MSK-IMPACT had been attempted were identified. Pathologic and clinical data were obtained from the medical record, and the results of MSK-IMPACT were examined.

RESULTS

In total, 784 EBUS-TBNA procedures were performed during the study period. MSK-IMPACT was requested for 115 malignant samples and was successful for 99 (86.1%), identifying an average of 12.7 mutations at a mean coverage depth of 806X. NGS was performed on paraffin-embedded cell blocks in 93 cases (93.9%) and on cell-free DNA in needle rinse fluid in 6 cases. The success rate of the assay improved significantly from the first third of cases (76.3%), to 92.3% for the final one-third of cases (p < 0.05).

CONCLUSIONS

EBUS-TBNA reliably provided adequate tissue for hybrid capture NGS, and is a suitable option for comprehensive NGS testing in patients with thoracic malignancies.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

- In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

- To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

- The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

- Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

- The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes ( ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes (ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes (ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Lung cancer samples preserved in liquid medium: One step beyond cytology

Lung cancer is one of the most common cancer types in men and women worldwide with a high mortality rate. World Health Organization (WHO) classification has accepted biopsy as the primary sample for lung cancer diagnosis, pathological classification and molecular testing for management of patients, yet, the use of alternative sampling procedures is highly encouraged. Bronchial cytological samples require a less invasive collection technique and may be suitable for pathological and molecular analysis and storage in liquid medium. Furthermore, the molecular analysis of bronchial cytological samples allows the detection of molecular biomarkers, which may be useful for the selection of molecular targeted therapies. Thus, the purpose of this review is to describe the usefulness of bronchial cytological samples preserved in liquid medium from lung cancer patients for pathological diagnosis and molecular investigation.

Double staining: diagnostic utility in non-small cell lung carcinoma in the era of tissue conservation

INTRODUCTION

In an era of precision medicine distinguishing pulmonary squamous cell carcinoma (SQCC) from adenocarcinoma (ADC) is vital for treatment. Immunohistochemical (IHC) staining for p40, p63 and Cytokeratin 5 (CK5) are useful for SQCC, while TTF-1 and Napsin-A can be used for confirming ADC. Fine needle aspiration (FNA) cell blocks (CB) have limited tissue, hence, double IHC staining is helpful for tissue conservation for molecular analysis.

MATERIALS AND METHODS

Thirty six confirmed lung SQCC and 45 ADC CB were selected for IHC. Double staining was performed with p40/CK5 and p63/CK5 on all SQCC, and with TTF-1/Napsin-A on all ADC. Results were positive if at least 5% of malignant cells were immunoreactive for the antigen.

RESULTS

P40/CK5 had (92%) sensitivity, (100%) specificity, (100%) positive predictive value (PPV), (91%) negative predictive value (NPV) and an overall diagnostic accuracy of (96%). By contrast, P63/CK5 double stains showed (92%) sensitivity, (80%) specificity, (85%) PPV, (89%) NPV and (86%) overall diagnostic accuracy, respectively. TTF-1/Napsin A staining for ADC showed a sensitivity of 80%, specificity of 96%, PPV of 97%, NPV of 71% and accuracy of 85%.

CONCLUSION

P40/CK5 double stain has higher specificity, PPV, NPV, and overall accuracy than P63/CK5 double stain in the diagnosis of lung SQCC. TTF-1/Napsin-A double staining is a valuable marker with high specificity, PPV, and diagnostic accuracy in diagnosing lung ADC. The usage of P40/CK5 and TTF-1/Napsin-A as a panel can be recommended for characterizing non-small cell carcinoma (NSCC) of the lung and for conserving tissue for molecular testing.

Metabonomics by proton nuclear magnetic resonance in human pleural effusions: A route to discriminate between benign and malignant pleural effusions and to target small molecules as potential cancer biomarkers

BACKGROUND

Cytopathology is a noninvasive and cost-effective method for detecting cancer cells in pleural effusions (PEs), although in many cases, the diagnostic performance is hindered by the paucity of significant cells or the lack of clear morphological criteria. This study presents the results of an omics approach to improving the diagnostic performance of PE cytology.

METHODS

Metabolic profiling with proton nuclear magnetic resonance (¹ H-NMR) was performed for 92 PEs (44 malignant cases of 8 different cancers and 48 benign cases of 7 nonneoplastic conditions). Light's criteria were used to further classify PEs as transudates or exudates, and ¹ H-NMR spectroscopy was used to differentiate malignant pleural effusions (mPEs) from benign pleural effusions (bPEs).

RESULTS

¹ H-NMR metabolic analysis showed clearly different spectra for mPEs and bPEs in the regions of the signals due to lipids, branched amino acids, and lactate, which were increased in mPEs. Transudates and exudates in bPEs were differentiated as well on the basis of the ¹ H-NMR signals from lipids and lipoproteins, which were increased in exudates.

CONCLUSIONS

Subject to validation in further larger studies, ¹ H-NMR metabonomics could be an effective and reliable ancillary tool for PE investigations and diagnoses. Cancer Cytopathol 2017;125:341-348. © 2017 American Cancer Society.