Molecular Testing in EBUS-TBNA Specimens of Lung Adenocarcinoma: A Study of Concordance Between Cell Block Method and Liquid-Based Cytology in Appraising Sample Cellularity and EGFR Mutations

Utility of SHOX2 and RASSF1A gene methylation detection on the residual cytology material from endobronchial ultrasound-guided transbronchial needle aspiration

Objective

This study aims to assess the effectiveness of Short Stature Homeobox 2 (SHOX2) and RAS Association Domain Family 1 Isoform A (RASSF1A) gene methylation detection in residual liquid-based cytology (LBC) materials from Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) and investigate the diagnostic accuracy of a comprehensive diagnostic approach.

Material and Methods

Between June 2022 and May 2023, a total of 110 cases that underwent EBUS-TBNA were enrolled in the study. SHOX2 and RASSF1A genes methylation detection using the residual cytological material, LBC, and cell block (CB) were conducted for each EBUS-TBNA case. The sensitivity and specificity of cytology, CB histopathology, SHOX2, and RASSF1A methylation in diagnosing EBUS-TBNA samples were determined based on follow-up data.

Results

Among the 72 cases confirmed as pulmonary carcinomas, the methylation test yielded positive results in 24 adenocarcinoma cases, 10 squamous cell carcinoma cases, and 14 small cell carcinoma cases. The sensitivity of the comprehensive diagnosis (combining LBC, CB, and methylation detection) in distinguishing metastatic pulmonary epithelial malignancies in mediastinal and hilar lymph nodes or masses from benign lesions was higher (97.22%, 70/72) than that of morphological diagnosis alone (LBC and CB) (88.89%, 64/72; P < 0.05).

Conclusion

SHOX2 and RASSF1A methylation detection demonstrates a high sensitivity and negative predictive value in the identification of pulmonary epithelial malignancies and holds promise as a valuable ancillary approach to enhance morphological diagnosis of EBUS-TBNA.

Whole Genome Sequencing in Advanced Lung Cancer can be Performed Using Diff-Quik Cytology Smears Derived from Endobronchial Ultrasound, Transbronchial Needle Aspiration (EBUS TBNA)

INTRODUCTION

Maximising alternative sample types for genomics in advanced lung cancer is important because bronchoscopic samples may sometimes be insufficient for this purpose. Further, the clinical applications of comprehensive molecular analysis such as whole genome sequencing (WGS) are rapidly developing. Diff-Quik cytology smears from EBUS TBNA is an alternative source of DNA, but its feasibility for WGS has not been previously demonstrated.

METHODS

Diff-Quik smears were collected along with research cell pellets.

RESULTS

Tumour content of smears were compared to research cell pellets from 42 patients, which showed good correlation (Spearman correlation 0.85, P < 0.0001). A subset of eight smears underwent WGS, which presented similar mutation profiles to WGS of the matched cell pellet. DNA yield was predicted using a regression equation of the smears cytology features, which correctly predicted DNA yield > 1500 ng in 7 out of 8 smears.

CONCLUSIONS

WGS of commonly collected Diff-Quik slides is feasible and their DNA yield can be predicted.

The basics of commonly used molecular techniques for diagnosis, and application of molecular testing in cytology

Molecular diagnostics has expanded to become the standard of care for a variety of solid tumor types. With limited diagnostic material, it is often desirable to use cytological preparations to provide rapid and accurate molecular results. This review covers important pre-analytic considerations and limitations, and a description of common techniques that the modern cytopathologist should understand when ordering and interpreting molecular tests in practice.

Evaluation of lung cancer biomarkers profile for the decision of targeted therapy in EBUS-TBNA cytological samples

BACKGROUND

Guidelines recommend performing biomarker tests for epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), BRAF and ROS proto-oncogene-1(ROS1) genes and protein expression of programmed death ligand-1(PD-L1) in patients with non-small lung cell carcinoma (NSCLC). Studies reported that endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) can provide sufficient material for cancer biomarker analyses, but there are still concerns about the subject.

AIM

The purpose of the study was to assess the adequacy of EBUS-TBNA for testing lung cancer biomarkers.

METHODS

We retrospectively reviewed patients with NSCLC whose EBUS-TBNA was analysed for EGFR, ALK, ROS-1, BRAF and PD-L1 expression between December 2011 and December 2020.

RESULTS

A total of 394 patients were enrolled in the study. EGFR mutation and ALK fusion were the most common studied biomarkers. EBUS-TBNA adequacy rate for biomarker tests was found 99.0% for EGFR, 99.1 for ALK, 97.2% for ROS1, 100% for BRAF and 99.3% for PD-L1 testing. Multivariate analysis revealed the histological type, history of treatment for NSCL, size, or 18-fluorodeoxyglucose uptake of sampled lesion did not show any association with TBNA adequacy for biomarker testing.

CONCLUSION

EBUS-TBNA can provide adequate material for biomarker testing for EGFR, ALK, ROS-1, BRAF and PD-L1 expression.

Impact of LBC fixative type and fixation time on molecular analysis of pancreatic cancer cells: A comparative study of cell morphology, antigenicity and nucleic acids

Introduction:

Liquid-based cytology (LBC) has been widely used since 2000. Next-Generation Sequencing (NGS) analysis of residual specimens in LBC fixative may also be performed for pancreatic cancer in the near future. We examined cell morphology, antigenicity and nucleic acids in pancreatic cancer cells at different fixation times using two types of LBC fixatives.

Methods:

PANC-1 cells were fixed in 1 ml CytoRich Red (CR), CytoRich Blue (CB), 95% ethanol (95% AL) or 10% neutral buffered formalin (10% NBF) and evaluated for cell area, antigenicity and nucleic acids with fixation times of 1 hour and 1, 3, 9, and 14 days. Antigenicity was evaluated by immunocytochemical staining for p53 and CK20, and nucleic acid fragmentation was assessed by real-time PCR.

Results:

There was no difference in total cell area between 1 hour and 14 day fixation times for the CR group, but the CB group showed cell contraction with 9 days fixation. In immunocytochemical staining, the CR group showed high p53 and CK20 positivity even after 14 days fixation. The CB group had a lower p53 positive rate than the CR group from 1 hour fixation. For nucleic acid fragmentation, Ct values for the CR group increased with fixation time. The CB group had consistently low Ct values.

Conclusion:

Different LBC fixatives and fixation time can have varying effects on cell morphology, antigenicity and nucleic acids in pancreatic cancer cells. Therefore, fixative type and fixation time should be considered for molecular testing on residual samples in LBC fixatives.

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.

Diagnostic value of liquid-based cytology test in intrathoracic lymph nodes and lung lesions sampled by endobronchial ultrasonography-transbronchial needle aspiration

BACKGROUNDS

Liquid-based cytology (LBC) has begun to be used in non-gynecological samples such as endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). This study aims to investigate the diagnostic value of LBC in intrathoracic lymph nodes and lung lesions sampled with EBUS-TBNA.

METHODS

In total, 174 cases that underwent EBUS-TBNA between July 2020 and February 2021 were included (75 and 99 cases were prepared using conventional and LBC methods, respectively). The two groups were compared in terms of diagnostic categories, number of slides, cell blocks, slides per location, locations sampled, immunohistochemical studies, sensitivity, specificity, and diagnostic accuracy.

RESULTS

The percentages of malignant, suspicious for malignancy, benign, and non-diagnostic (ND) cases were 51.8%, 1.1%, 39.6%, and 7.5%, respectively. The LBC and conventional group (CG) had similar rates in the diagnostic categories, except for ND (3.0% and 13.3%, respectively). The sensitivity of LBC and CG were 90.4% and 85.7%, respectively. There were no differences in the specificity and diagnostic accuracy between groups. There was a statistically significant difference between groups in terms of the number of slides, number of slides per location, number of cell blocks, and locations sampled (p < .001, p < .001, p < .05, p < .05).

CONCLUSION

The LBC technique can be used for samples taken with EBUS-TBNA. Rapid fixation and the absence of artificial problems greatly reduce the rate of ND samples in LBC slides. Other important advantages are a lower number of slides to examine and a greater number of cell blocks.

Evaluation of liquid based cytology in detection of EGFR mutation in NSCLC by large samples

Background

Cytology samples are the main resources to detect driver oncogene alterations for advanced lung cancer patients. To explore the value of liquid-based cytology in the detection of epidermal growth factor receptor (EGFR) mutation in non-small cell lung cancer (NSCLC), we analyzed data from a large cohort of EGFR mutation-positive patients.

Methods

We analyzed the clinicopathological characteristics of 8,029 NSCLC cases tested for EGFR mutation by liquid-based cytology specimens and 1,934 NSCLC cases tested by formalin-fixed and paraffine-embedded (FFPE) samples in the Shanghai Pulmonary Hospital from September 2015 to December 2019. Before detection, we evaluated the number of tumor cells in the liquid-based cytology slide, and samples with more than 50 tumor cells and visible sediment were selected for DNA extraction after centrifugation.

Results

The positive rate of EGFR mutation in liquid-based cytology-tested cases was 47.18%, higher than the 41.37% tested through FFPE sample (P<0.01). Accordingly, the mutation rate of EGFR in adenocarcinoma (AC) and NSCLC was higher than that of the FFPE sample (60.01% vs. 54.15%, P<0.01; 30.54% vs. 21.99%, P<0.01). The positive rate of EGFR mutation in pleural effusion was 62.67%, which was the highest rate among liquid-based cytology sample t (P<0.01).

Conclusions

Using quality control and standard procedure, it was found that liquid-based cytology specimen testing is a convenient and reliable method of EGFR detection, as validated by analysis of a large cohort. EGFR mutation detection should also be carried out in NSCLC patients diagnosed by cytology more than in AC patients.

Molecular and Genomic Profiling of Lung Cancer in the Era of Precision Medicine: A Position Paper from the Italian Association of Thoracic Oncology (AIOT)

The identification of the optimal cancer treatment has become progressively more intricate for non-small-cell lung cancer (NSCLC) patients due to the multitude of options available. The testing of biomarkers to predict clinical responses to therapies is pivotal to stratify the patients based on the molecular features of their tumors. The number of actionable genetic alterations to be tested is increasing together with the comprehension of the molecular mechanisms underlying tumor growth and development. The possibility of using next generation sequencing-based approaches enhanced the acquisition of genetic data with potential clinical usefulness, and favored the integration of precision medicine in clinical practice. The availability of targeted sequencing panels that cover genetic alterations in hundreds of genes allows the performance of a comprehensive genomic profiling (CGP) of lung tumors. However, different issues still need to be solved, from the tissue needed for next generation sequencing analysis, to the choice of the test and its interpretation in the clinical context. This position paper from the Italian Association of Thoracic Oncology (AIOT) summarizes the results of a discussion from a Precision Medicine Panel meeting on the challenges to bringing CGP and, therefore, precision medicine into the daily clinical practice.

Cytologic features and diagnostic value of PeriView FLEX transbronchial needle aspiration targeting pulmonary nodules

BACKGROUND

Transbronchial needle aspiration (TBNA) of peripheral lung nodules can be difficult with conventional devices due to their limited flexibility. A promising new technology for accessing these lesions is the PeriView FLEX TBNA device, which has a flexible spiral-grooved needle. The present study reports the unique cytologic features, diagnostic value, and potential pitfalls of PeriView FLEX TBNA specimens.

METHODS

This study retrospectively evaluates 113 consecutive cases of lung nodules sampled using the PeriView FLEX device with radial endobronchial ultrasound guidance.

RESULTS

PeriView FLEX specimens were satisfactory for evaluation in 111 of 113 cases (98%). A diagnosis of malignancy was made on 64 specimens (57%), with 100% specificity and 70% sensitivity for malignancy. In 4 cases, the PeriView FLEX sample was the only specimen from bronchoscopy that was diagnostic of malignancy. Of the 64 PeriView FLEX specimens with malignant cells, 58 (91%) were adequate for immunohistochemistry and 44 (69%) were adequate for molecular genetic testing. Potential pitfalls were largely ameliorated through education regarding the unique features of PeriView FLEX samples, such as the expected abundance of anthracotic pigment and the paucity of lymphocytes.

CONCLUSIONS

TBNA using the PeriView FLEX device to sample pulmonary nodules contributed to the diagnostic value of bronchoscopy and tended to provide sufficient tissue for ancillary studies. Many of the possible pitfalls may be avoided through consideration of the unique cytologic features associated with this novel sampling method.

The role of endobronchial ultrasound-guided transbronchial needle aspiration liquid-based cytology in the diagnosis of mediastinal lymphadenopathy

BACKGROUND

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive, reliable technique for sampling mediastinal lymph nodes (LNs). Liquid-based cytology (LBC) is widely used for cervical cancer screening because it provides reliable and feasible results. The present study aimed to evaluate effectiveness of the combination of EBUS-TBNA and LBC in the diagnosis of mediastinal lymphadenopathy.

METHODS

A total of 602 LNs that were retrospectively analyzed were sampled in 442 patients who underwent EBUS-TBNA between January 2014 and December 2016. The histopathological result of TBNA tissue or cell blocks was considered as the gold standard to evaluate diagnostic utility of LBC and conventional smears (CS) for the diagnosis of mediastinal lymphadenopathy.

RESULTS

Of the 602 LNs, 265 were mediastinal LN metastases from lung cancer, four were lymphoma, and 333 were benign. The sensitivity of LBC and CS in the diagnosis of mediastinal LN metastases from lung cancer was 72.8% and 63%, respectively, and the specificity was 98.5% and 97%, respectively. The positive predictive values for LBC and CS were 97.5% and 94.4%, respectively, whereas the negative predictive values were 82.2% and 76.9%, respectively. The accuracy of LBC and CS was 88% and 83.7%, respectively. The diagnostic value of LBC was significantly higher than that of CS (P = .001).

CONCLUSIONS

The combination of EBUS-TBNA and LBC is a highly reliable and feasible procedure that optimizes diagnostic utility for the diagnosis of lung cancer and mediastinal LN staging.