Team work and cytopathology molecular diagnosis of solid pancreatic lesions

Endoscopic ultrasound-guided fine-needle aspiration pancreatic adenocarcinoma samples yield adequate DNA for next-generation sequencing: A cohort analysis

BACKGROUND

Genetic tests are increasingly performed for the management of unresectable pancreatic cancer. For genotyping aimed samples current guidelines recommend using core specimens, although based on moderate quality evidence. However, in clinical practice among the endoscopic ultrasound (EUS) guided tissue acquisition methods, fine needle aspiration (FNA) is the most widely performed.

AIM

To assess the adequacy for next generation sequencing (NGS) of the DNA yielded from EUS-FNA pancreatic adenocarcinoma (PDAC) samples.

METHODS

Between November 2018 and December 2021, 105 patients with PDAC confirmed by EUS-FNA were included in the study at our tertiary gastroenterology center. Either 22 gauge (G) or 19G FNA needles were used. One pass was dedicated to DNA extraction. DNA concentration and purity (A260/280, A260/230) were assessed by spectrophotometry. We assessed the differences in DNA parameters according to needle size and tumor characteristics (size, location) and the adequacy of the extracted DNA for NGS (defined as A260/280 ≥ 1.7, and DNA yield: ≥ 10 ng for amplicon based NGS, ≥ 50 ng for whole exome sequencing [WES], ≥ 100 ng for whole genome sequencing [WGS]) by analysis of variance and t-test respectively. Moreover, we compared DNA purity parameters across the different DNA yield categories.

RESULTS

Our cohort included 49% male patients, aged 67.02 ± 8.38 years. The 22G needle was used in 71% of the cases. The DNA parameters across our samples varied as follows: DNA yield: 1289 ng (inter quartile range: 534.75-3101), A260/280 = 1.85 (1.79-1.86), A260/230 = 2.2 (1.72-2.36). DNA yield was > 10 ng in all samples and > 100 ng in 93% of them (one sample < 50 ng). There were no significant differences in the concentration and A260/280 between samples by needle size. Needle size was the only independent predictor of A260/230 which was higher in the 22G samples (P = 0.038). NGS adequacy rate was 90% for 19G samples regardless of NGS type, and for 22G samples it reached 89% for WGS adequacy and 91% for WES and amplicon based NGS. Samples with DNA yield > 100 ng had significantly higher A260/280 (1.89 ± 0.32 vs 1.34 ± 0.42, P = 0.013). Tumor characteristics were not corelated with the DNA parameters.

CONCLUSION

EUS-FNA PDAC samples yield DNA adequate for subsequent NGS. DNA amount was similar between 22G and 19G FNA needles. DNA purity parameters may vary indirectly with needle size.

Prediction of Biomarker Expression on Primary Pancreatic Ductal Adenocarcinoma Tissues Using Fine-Needle Biopsies: Paving the Way for a Patient-Tailored Molecular Imaging Approach

BACKGROUND

Targeted molecular imaging may improve tumor cell identification during diagnosis and resection of pancreatic ductal adenocarcinoma (PDAC). Although many molecular imaging biomarkers are (over)expressed in PDAC, intertumoral heterogeneity of biomarker expression hampers universal tracer administration. Preoperative, patient-specific screening and selection of the most optimal biomarker could therefore improve tumor delineation.

OBJECTIVE

This study evaluated whether fine-needle biopsy (FNB) specimens could be used to preoperatively predict biomarker expression in the corresponding primary PDAC specimen.

METHODS

Expression of previously identified PDAC biomarkers α_vβ₆, CEACAM5, EGFR, mesothelin, Le^a/c/x, and sdi-Le^a on FNB and corresponding primary tumor (PT) specimens (n = 45) was evaluated using immunohistochemistry and quantified using a semi-automated image analysis workflow.

RESULTS

Biomarker expression on FNB and PT tissues showed high concordance (∆H-score ≤ 50), i.e. was present in 62% of cases for α_vβ₆, 61% for CEACAM5, 85% for EGFR, 69% for mesothelin, 76% for Le^a/c/x, and 79% for sdi-Le^a, indicating high concordance. Except for α_vβ₆, biomarker expression on FNB tissues was positively correlated with PT expression for all biomarkers. Subgroup analyses showed that neoadjuvant therapy (NAT) had no major and/or significant effect on concordance, expression difference and, except for mesothelin, correlation of biomarker expression between FNB and PT tissues.

CONCLUSION

This study demonstrated that biomarker expression in FNB tissues is predictive for PT expression, irrespective of the application of NAT. These findings thereby provide the foundation for the clinical application of an FNB-based biomarker-screening workflow, eventually facilitating a patient-specific approach of molecular imaging tracer administration in PDAC.

New era for pancreatic endoscopic ultrasound: From imaging to molecular pathology of pancreatic cancer

With recent advances in molecular pathology and the development of new chemotherapy regimens, the knowledge of the molecular alterations of pancreatic ductal adenocarcinoma (PDAC) is becoming appealing for stratifying patients for prognosis and response to a defined treatment. Archival formalin-fixed, paraffin-embedded samples are a useful source of genomic deoxyribonucleic acid; nevertheless, most studies employed formalin-fixed, paraffin-embedded samples deriving from surgical specimens, which are therefore representative of <20% of PDAC patients. Indeed, the development of a reliable methodology for endoscopic ultrasound-guided tissue acquisition, stabilization, and analysis is crucial for the development of molecular markers for clinical use in order to achieve “personalized medicine”. With the development of new needles, this technique is able to retrieve a high quantity and quality of PDAC tissue that can be used not only for diagnosis but also for mutational and transcriptome evaluations and for the development of primary cell or tissue cultures. In the present editorial, we discuss the current knowledge regarding the use of endoscopic ultrasound as a tool to obtain samples for molecular analyses, its possible pitfalls, and its use for the development of disease models such as xenografts or organoids.

Invited review-next-generation sequencing: a modern tool in cytopathology

In recent years, cytopathology has established itself as an independent diagnostic modality to guide clinical management in many different settings. The application of molecular techniques to cytological samples to identify prognostic and predictive biomarkers has played a crucial role in achieving this goal. While earlier studies have demonstrated that single biomarker testing is feasible on cytological samples, currently, this provides only limited and increasingly insufficient information in an era where an increasing number of biomarkers are required to guide patient care. More recently, multigene mutational assays, such as next-generation sequencing (NGS), have gained popularity because of their ability to provide genomic information on multiple genes. The cytopathologist plays a key role in ensuring success of NGS in cytological samples by influencing the pre-analytical steps, optimizing preparation types and adequacy requirement in terms of cellularity and tumor fraction, and ensuring optimal nucleic acid extraction for DNA input requirements. General principles of the role and potential of NGS in molecular cytopathology in the universal healthcare (UHC) European environment and examples of principal clinical applications were discussed in the workshop that took place at the 30th European Congress of Pathology in Bilbao, European Society of Pathology, whose content is here comprehensively described.

Touch imprint cytology on endoscopic ultrasound fine-needle biopsy provides comparable sample quality and diagnostic yield to standard endoscopic ultrasound fine-needle aspiration specimens in the evaluation of solid pancreatic lesions

OBJECTIVES

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is the gold standard for the diagnosis of solid pancreatic lesions (SPLs). Cytological samples can also be obtained using touch imprint cytology (TIC) on EUS fine-needle biopsy (FNB) specimens. We aimed to compare sample quality and diagnostic yield of EUS-FNA-standard cytology (EUS-FNA-SC) to that of EUS-FNB-TIC in a series of patients with SPLs.

METHODS

Thirty-two consecutive patients referred for EUS-tissue acquisition of SPLs who underwent rapid on-site evaluation of both EUS-FNA-SC and paired EUS-FNB-TIC during the same endoscopic session were retrospectively identified. Sample quality (evaluated in terms of blood contamination, presence of clots, tissue casts, cellularity, and necrosis) and diagnostic yield were compared between the techniques.

RESULTS

The mean number of passes to reach diagnosis at rapid on-site evaluation was similar between EUS-FNA-SC and EUS-FNB-TIC (1.09 ± 0.3 vs 1.13 ± 0.34, P = .711). EUS-FNA-SC scores of sample quality were comparable to those of EUS-FNB-TIC (blood contamination, 2.47 ± 1.11 vs 2.25 ± 1.14, P = .109; clots, 1.25 ± 0.76 vs 1.19 ± 0.69, P = .624; tissue casts, 3.56 ± 0.88 vs 3.59 ± 1.09, P = .872; cellularity, 2.84 ± 1.11 vs 3.09 ± 1.09, P = .244; necrosis, 2.25 ± 1.08 vs 2.53 ± 1.02 P = .059; total score, 12.38 ± 2.88 vs 17.66 ± 2.38, P = .536). Adequacy, sensitivity and diagnostic accuracy of the two sampling techniques were equal (93.7%, 90.6% and 90.6%, respectively).

CONCLUSIONS

EUS-FNB-TIC provides comparable samples to those of EUS-FNA-SC and combines the benefits of cytology and histology for the evaluation of SPLs by employing a single needle during the same endoscopic procedure.

Pancreatic Cytology

The diagnostic approach to pancreaticobiliary disease requires a multidisciplinary team in which the cytopathologist plays a crucial role. Fine-needle aspiration, obtained by endoscopic ultrasound, is the diagnostic test of choice for pancreatic lesions. Preoperative clinical management depends on many factors, many of which rely on accurate cytologic assessment. Pancreaticobiliary cytology is wrought with diagnostic pitfalls. Clinical history, imaging studies, cytology samples, and ancillary tests, including immunohistochemistry, biochemical analysis, and genetic sequencing, are integral to forming a complete diagnosis and guiding optimal patient management. This article reviews clinical aspects and the diagnostic work-up of commonly encountered diagnostic entities within the field of pancreatic cytology.

Endoscopic Ultrasound Imaging for Differential Diagnosis of Pancreatic Neoplasms: A 7-Year Study in a Chinese Population

Background

Currently, non-invasive methods for screening pancreatic cancer are lacking. There is little information regarding whether endoscopic ultrasound (EUS) imaging has a discriminatory ability for detecting benign and malignant pancreatic neoplasms. In this study, we retrospectively analyzed the demographic, clinicopathologic, and EUS features and follow-up information.

Material/Methods

A total of 58 patients with pancreatic neoplasms who underwent endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) over a 7-year period (2009–2016) at our Department of Digestive Diseases were enrolled in our study.

Results

Of the 58 patients, 38 (65.5%) were diagnosed with malignant pancreatic neoplasms and 20 (34.5%) were benign ones. Of all the EUS findings, size of neoplasm (P=0.037) and regularity of margin (P=0.011) were significantly different between malignant and benign pancreatic neoplasms. However, age, sex, location, echo pattern, and dilation of main pancreatic duct did not show any significant difference (P>0.05). Size combined with regularity to detect malignant pancreatic neoplasms showed the following diagnostic values: sensitivity, 73.68%; specificity, 90%; positive predictive value, 76.60%; negative predictive value 81.82%; and area under the receiver operating characteristic curve, 0.887 (95% CI: 0.777–0.955, P<0.0001).

Conclusions

Our results showed the high value of EUS for differentiating malignant pancreatic neoplasms from benign ones. Due to this and its non-invasive nature, EUS should be the first-line method for detection of neoplastic pancreatic lesions.

A quarter century of EUS-FNA: Progress, milestones, and future directions

Tissue acquisition using EUS has considerably evolved since the first EUS-FNA was reported 25 years ago. Its introduction was an important breakthrough in the endoscopic field. EUS-FNA has now become a part of the diagnostic and staging algorithm for the evaluation of benign and malignant diseases of the gastrointestinal tract and of the organs in its proximity, including lung diseases. This review aims to present the history of EUS-FNA development and to provide a perspective on the recent developments in procedural techniques and needle technologies that have significantly extended the role of EUS and its clinical applications. There is a bright future ahead for EUS-FNA in the years to come as extensive research is conducted in this field and various technologies are continuously implemented into clinical practice.

Molecular Diagnostics in Pathology: Time for a Next-Generation Pathologist?

Context.—

Comprehensive molecular investigations of mainstream carcinogenic processes have led to the use of effective molecular targeted agents in most cases of solid tumors in clinical settings.

Objective.—

To update readers regarding the evolving role of the pathologist in the therapeutic decision-making process and the introduction of next-generation technologies into pathology practice.

Data Sources.—

Current literature on the topic, primarily sourced from the PubMed (National Center for Biotechnology Information, Bethesda, Maryland) database, were reviewed.

Conclusions.—

Adequate evaluation of cytologic-based and tissue-based predictive diagnostic biomarkers largely depends on both proper pathologic characterization and customized processing of biospecimens. Moreover, increased requests for molecular testing have paralleled the recent, sharp decrease in tumor material to be analyzed—material that currently comprises cytology specimens or, at minimum, small biopsies in most cases of metastatic/advanced disease. Traditional diagnostic pathology has been completely revolutionized by the introduction of next-generation technologies, which provide multigene, targeted mutational profiling, even in the most complex of clinical cases. Combining traditional and molecular knowledge, pathologists integrate the morphological, clinical, and molecular dimensions of a disease, leading to a proper diagnosis and, therefore, the most-appropriate tailored therapy.