Characterization of endoscopic ultrasound fine-needle aspiration cytology by targeted next-generation sequencing and theranostic potential

Next-generation sequencing analysis of endometrial screening liquid-based cytology specimens: a comparative study to tissue specimens

Background

Liquid-based cytology (LBC) is now a widely used method for cytologic screening and cancer diagnosis. Since the cells are fixed with alcohol-based fixatives, and the specimens are stored in a liquid condition, LBC specimens are suitable for genetic analyses.

Methods

Here, we established a small cancer gene panel, including 60 genes and 17 microsatellite markers for next-generation sequencing, and applied to residual LBC specimens obtained by endometrial cancer screening to compare with corresponding formalin-fixed paraffin-embedded (FFPE) tissues.

Results

A total of 49 FFPE and LBC specimens (n = 24) were analyzed, revealing characteristic mutations for endometrial cancer, including PTEN, CTNNB1, PIK3CA, and PIK3R1 mutations. Eight cases had higher scores for both tumor mutation burden (TMB) and microsatellite instability (MSI), which agree with defective mismatch repair (MMR) protein expression. Paired endometrial LBC, and biopsied and/or resected FFPE tissues from 7 cases, presented almost identical mutations, TMB, and MSI profiles in all cases.

Conclusion

These findings demonstrate that our ad hoc cancer gene panel enabled the detection of therapeutically actionable gene mutations in endometrial LBC and FFPE specimens. Endometrial cancer LBC specimens offer an alternative and affordable source of molecular testing materials.

Factors of Endoscopic Ultrasound-Guided Tissue Acquisition for Successful Next-Generation Sequencing in Pancreatic Ductal Adenocarcinoma

BACKGROUND/AIMS

Recent advances in understanding the genetics of pancreatic ductal adenocarcinoma (PDAC) have led to the potential for a personalized approach. Several studies have described the feasibility of generating genetic profiles of PDAC with next-generation sequencing (NGS) of samples obtained through endoscopic ultrasound-guided tissue acquisition (EUS-TA). The aim of this study was to find the best EUS-TA approach for successful NGS of PDAC.

METHODS

We attempted to perform NGS with tissues from 190 patients with histologically proven PDAC by endoscopic ultrasound-guided fine-needle aspiration and endoscopic ultrasound-guided fine-needle biopsy at Samsung Medical Center between November 2011 and February 2015. The medical records of these patients were retrospectively reviewed for parameters including tumor factors (size, location, and T stage), EUS-TA factors (needle gauge [G], needle type, and number of needle passes) and histologic factors (cellularity and blood contamination). The sample used for NGS was part of the EUS-TA specimen that underwent cytological and histological analysis.

RESULTS

NGS could be successfully performed in 109 patients (57.4%). In the univariate analysis, a large needle G (p=0.003) and tumor located in the body/tail (p=0.005) were associated with successful NGS. The multivariate logistic regression analysis revealed that the needle G was an independent factor of successful NGS (odds ratio, 2.19; 95% confidence interval, 1.08 to 4.47; p=0.031).

CONCLUSIONS

The needle G is an independent factor associated with successful NGS. This finding may suggest that the quantity of cells obtained from EUS-TA specimens is important for successful NGS.

Theranostic Gastrointestinal Endoscopy: Bringing Healing Light to the Lumen

Current conventional endoscopes have restricted the accuracy of treatment delivery and monitoring. Over the past decade, there have been major developments in nanotechnology and light triggered therapy, potentially allowing a better detection of challenging lesions and targeted treatment of malignancies in the gastrointestinal tract. Theranostics is a developing form of personalized medicine because it combines diagnosis and targeted treatment delivered in one step using advances in nanotechnology. This review describes the light-triggered therapies (including photodynamic, photothermal, and photoimmunotherapies), nanotechnological advances with nanopowder, nanostent, nanogels, and nanoparticles, enhancements brought to endoscopic ultrasound, in addition to experimental endoscopic techniques, combining both enhanced diagnoses and therapies, including a developed prototype of a “smart” multifunctional endoscope for localized colorectal cancer, near-infrared laser endoscope targeting the gastrointestinal stromal tumors, the concept of endocapsule for obscure gastrointestinal bleed, and a proof-of-concept therapeutic capsule using ultrasound-mediated targeted drug delivery. Hence, the following term has been proposed encompassing these technologies: “Theranostic gastrointestinal endoscopy.” Future efforts for integration of these technologies into clinical practice would be directed toward translational and clinical trials translating into a more personalized and interdisciplinary diagnosis and treatment, shorter procedural time, higher precision, higher cost-effectiveness, and less need for repetitive procedures.

Comparison of endoscopic ultrasound tissue acquisition methods for genomic analysis of pancreatic cancer

BACKGROUND AND AIM

Tumor genotyping may allow for improved prognostication and targeted therapy for pancreatic ductal adenocarcinoma (PDAC). We aimed to compare endoscopic ultrasonography (EUS) with fine needle aspiration (FNA) to fine needle biopsy (FNB) for obtaining sufficient tissue for genomic analysis and theranostic potential.

METHODS

A retrospective cohort study of patients that underwent EUS-FNA or EUS-FNB with either positive or suspicious cytology for PDAC between March 2016 and December 2017. Demographic, procedural, and cytology data were recorded. Genetic alterations were recorded, and Kaplan-Meier survival curves were calculated.

RESULTS

The study included 167 patients: 145 patients had FNA and 22 patients underwent FNB. Overall, 117 samples (70.1%) were sufficient for targeted next-generation sequencing. FNB resulted in a higher proportion of patients with sufficient samples compared with FNA (90.9% vs 66.9%; P = 0.02). In multivariable modeling, only FNB (odds ratio 4.95, 95% confidence interval 1.11-22.05, P = 0.04) was associated with sufficient sampling for genomic testing. FNB was more likely to obtain sufficient tissue from tumors ≤ 3 cm (100% vs 68.4%, P = 0.017) and tumors located in the head/neck of the pancreas (100% vs 63.1%, P = 0.03) compared with FNA. The most commonly identified alterations were in KRAS (88%), TP53 (68%), and SMAD4 (16%).

CONCLUSIONS

Endoscopic ultrasonography can reliably obtain sufficient tissue from PDAC for targeted genomic sequencing for prognostication and theranostics. FNB should be considered when tumor genotyping is requested, especially for tumors ≤ 3 cm or tumors located in the head/neck of the pancreas.

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.

Salvaging the supernatant: next generation cytopathology for solid tumor mutation profiling

With the expanding role of targeted therapy in patients with solid tumors, pathologists face the daunting task of having to maximize limited volume tissue obtained by fine needle aspiration for a variety of molecular tests. While most molecular studies on fine needle aspiration samples have been reported using cellular material, recent studies have shown that a substantial amount of DNA can be retrieved from the supernatant fluid of aspirate needle rinses after cell pelleting for cytospin or cell block preparations. In routine clinical workflow, the supernatant is discarded; however this fluid may provide a complementary source of DNA for tumor mutational profiling. In this study, we evaluated the post-centrifuged supernatant from 25 malignant and 10 benign fine needle aspiration needle rinses. The mean and median DNA yields from the supernatants were 445 ng and 176.4 ng (range, 15.1-2958 ng), respectively. Next generation sequencing using the Ion AmpliSeq Cancer Hotspot Panel v2 detected somatic mutations in all 25 malignant samples. No mutations were detected in any of the benign samples tested. When available, mutations detected in the supernatant fluid were compared to the next generation sequencing analysis performed on a prior or concurrent surgical specimen from the same patient and showed 100% concordance. In a subset of cases (n = 19) mutations in EGFR, KRAS, BRAF, PIK3CA, and NRAS were successfully confirmed by droplet digital PCR, providing an orthogonal platform for mutation analysis. In summary, in this study we show that post centrifuged supernatants from fine needle aspiration needle rinses can provide a robust substrate for expanded mutation profiling by next generation sequencing, as well as hotspot mutation testing by droplet digital PCR. The ability to detect somatic mutations from otherwise discarded supernatant fluids offers the ability to triage and effectively utilize limited volume fine needle aspiration samples when multiple molecular tests are requested, without the need to re-biopsy for additional tissue samples.

Successful creation of pancreatic cancer organoids by means of EUS-guided fine-needle biopsy sampling for personalized cancer treatment

BACKGROUND AND AIMS

Pancreatic cancer organoids are tumor models of individualized human pancreatic ductal adenocarcinoma (PDA), created from surgical specimens and used for personalized treatment strategies. Unfortunately, most patients with PDA are not operative candidates. Creation of human PDA organoids at the time of initial tumor diagnosis is therefore critical. Our aim was to assess the feasibility of creating human PDA organoids by EUS fine-needle biopsy (EUS-FNB) sampling in patients with PDA.

METHODS

In this prospective clinical trial in patients referred to evaluate a pancreatic mass, EUS-FNA was performed for initial onsite diagnosis. Two additional needle passes were performed with a 22-gauge FNB needle for organoid creation. Primary outcome was successful isolation of organoids within 2 weeks of EUS-FNB sampling (P0, no passages), confirmed by organoid morphology and positive genotyping.

RESULTS

Thirty-seven patients with 38 PDA tumors were enrolled. Successful isolation of organoids (P0) was achieved in 33 of 38 tumors (87%). Establishment of PDA organoid lines for ≥5 passages of growth (P5, five passages) was reached in 25 of 38 tumors (66%). In the single patient with successful P5 FNB sampling-derived and P5 surgically derived organoids, there was identical matching of specimens. There were no serious adverse events. Two patients developed bleeding at the EUS-FNB puncture site requiring hemostasis clips.

CONCLUSIONS

Pancreatic cancer organoids can be successfully and rapidly created by means of EUS-FNB sampling using a 22-gauge needle at the time of initial diagnosis. Successful organoid generation is essential for precision medicine in patients with pancreatic cancer in whom most are not surgically resectable. (Clinical trial registration number: NCT03140592.).

Feasibility of Endobronchial Ultrasound-guided Transbronchial Needle Aspiration Cytology Specimens for Next Generation Sequencing in Non-small-cell Lung Cancer

INTRODUCTION

Next generation sequencing (NGS) testing of lung cancer is recommended by guidelines, and endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA) often provides the only material available for testing. Previous studies have demonstrated successful NGS testing on cell block samples obtained by EBUS; however, cytology smears provide a more reliable sample with better DNA quality for testing. In this study, we aimed to determine the success rate of OncoScreen (50 gene) and OncoPlus (1213 gene) panel NGS testing of cytology samples obtained by EBUS utilizing 22- and 25-gauge needles.

METHODS

Fifty-four patients underwent EBUS-TBNA of lung cancer for which NGS testing was requested. Data was analyzed for needle gauge, cytologic assessment, NGS test success, and sample type (cytology smear or cell block) used for testing.

RESULTS

Eighty-five NGS tests were ordered on 54 samples. Overall, 95.3% of samples had successful testing. OncoScreen and OncoPlus panels were successful 98.0% and 91.4% of the time, respectively. Cytology smears provided testing material for 85% of the tests. OncoScreen testing was successful in 97.5% and 100% of the 22- and 25-gauge samples, respectively (P = 1.00). OncoPlus testing was successful in 91.3% and 100% of the 22- and 25-gauge samples, respectively (P = 1.00).

CONCLUSIONS

NGS can be reliably performed on cytology smears obtained from EBUS-TBNA. The size of the needle does not seem to affect the success rate of small or large panel NGS tests.

Assessment of pancreatic neuroendocrine tumor cytologic genotype diversity to guide personalized medicine using a custom gastroenteropancreatic next-generation sequencing panel

Background

Recent genetic studies have highlighted that alterations in MEN1, chromatin remodeling genes, and mammalian target of rapamycin (mTOR) pathway genes are the most frequent molecular events identified in pancreas neuroendocrine tumors (pNETs). The prognostic or predictive impact of these biomarkers and other less frequently observed aberrations, i.e. PTEN, TSC2 and PIK3CA are relatively unknown. The aims of this targeted next generation sequencing (NGS) study were to assess tumor cytology genotype diversity, to survey for potential adverse prognostic biomarkers and the prevalence of mTOR pathway variants.

Methods

Using a custom 15 gene gastroenteropancreatic neuroendocrine tumor panel, targeted NGS of archived (2002-2013) primary pNETs (n=90) and pNET liver metastasis (n=32) cytology smears was performed.

Results

The genetic variant landscape revealed that 21% and 28% of primary and metastatic liver pNETs harbored ≥ 2 variants per tumor, respectively. The most prevalent primary tumor variants were in the MEN1 (42%), DAXX (11%), ATRX (10%), and TSC2 (8%) genes. Patients harboring aberrations in TSC2, KRAS or TP53 were more likely to experience disease progression and reduced overall survival, when compared to individuals who were wild-type. The prevalence of these potential prognostic biomarkers in early disease was observed in 3.3% of the primary tumor cohort. mTOR pathway variants including alterations in PTEN, TSC2 and PIK3CA were identified in 10% and 12.5% of primary tumors and pNET liver metastasis, respectively.

Conclusion

Cytology based tumor genotyping revealed a broad spectrum of genetic variants including possible adverse prognostic biomarkers, reflective of an aggressive phenotype. It also demonstrated the prevalence of potential predictive biomarkers for mTOR pathway inhibitor sensitivity.

Next-Generation Sequencing in Oncology: Genetic Diagnosis, Risk Prediction and Cancer Classification

Next-generation sequencing (NGS) technology has expanded in the last decades with significant improvements in the reliability, sequencing chemistry, pipeline analyses, data interpretation and costs. Such advances make the use of NGS feasible in clinical practice today. This review describes the recent technological developments in NGS applied to the field of oncology. A number of clinical applications are reviewed, i.e., mutation detection in inherited cancer syndromes based on DNA-sequencing, detection of spliceogenic variants based on RNA-sequencing, DNA-sequencing to identify risk modifiers and application for pre-implantation genetic diagnosis, cancer somatic mutation analysis, pharmacogenetics and liquid biopsy. Conclusive remarks, clinical limitations, implications and ethical considerations that relate to the different applications are provided.

Lymph Node Fine-Needle Cytology: Beyond Flow Cytometry

Lymph node (LN) fine-needle cytology (FNC) coupled with flow cytometry immunophenotyping provides relevant information for the diagnosis of non-Hodgkin lymphoma (NHL). Numerous studies have shown FNC samples to be suitable for different molecular procedures; in this review, some of the molecular procedures most commonly employed for NHL are briefly described and evaluated in this perspective. Fluorescence in situ hybridization and chromogenic in situ hybridization are briefly described. Polymerase chain reaction (PCR)-based assays are used to identify and quantify mutations and translocations, namely immunoglobulin (IGH) and T-cell receptor rearrangements by clonality testing and IGVH somatic hypermutations either by Sanger sequencing, single-strand conformational polymorphisms or RT-PCR strategies. High-throughput technologies (HTT) encompass numerous and different diagnostic tools that share the capacity of multiple molecular investigation and sample processing in a fast and reproducible manner. HTT includes gene expression profiling, comparative genomic hybridization, single-nucleotide polymorphism arrays and next-generation sequencing technologies. A brief description of these tools and their potential application to LN FNC is reported. The challenge for FNC will be to achieve new knowledge and apply new technologies to FNC, exploiting its own basic qualities.

Targeted next generation sequencing of endoscopic ultrasound acquired cytology from ampullary and pancreatic adenocarcinoma has the potential to aid patient stratification for optimal therapy selection

BACKGROUND & AIMS

Less than 10% of registered drug intervention trials for pancreatic ductal adenocarcinoma (PDAC) include a biomarker stratification strategy. The ability to identify distinct mutation subsets via endoscopic ultrasound fine needle aspiration (EUS FNA) molecular cytology could greatly aid clinical trial patient stratification and offer predictive markers. We identified chemotherapy treatment naïve ampullary adenocarcinoma and PDAC patients who underwent EUS FNA to assess multigene mutational frequency and diversity with a surgical resection concordance assessment, where available.

METHODS

Following strict cytology smear screening criteria, targeted next generation sequencing (NGS) using a 160 cancer gene panel was performed.

RESULTS

Complete sequencing was achieved in 29 patients, whereby 83 pathogenic alterations were identified in 21 genes. Cytology genotyping revealed that the majority of mutations were identified in KRAS (93%), TP53 (72%), SMAD4 (31%), and GNAS (10%). There was 100% concordance for the following pathogenic alterations: KRAS, TP53, SMAD4, KMT2D, NOTCH2, MSH2, RB1, SMARCA4, PPP2R1A, PIK3R1, SCL7A8, ATM, and FANCD2. Absolute multigene mutational concordance was 83%. Incremental cytology smear mutations in GRIN2A, GATA3 and KDM6A were identified despite re-examination of raw sequence reads in the corresponding resection specimens.

CONCLUSIONS

EUS FNA cytology genotyping using a 160 cancer gene NGS panel revealed a broad spectrum of pathogenic alterations. The fidelity of cytology genotyping to that of paired surgical resection specimens suggests that EUS FNA represents a suitable surrogate and may complement the conventional stratification criteria in decision making for therapies and may guide future biomarker driven therapeutic development.

Optimizing the DNA yield for molecular analysis from cytologic preparations

BACKGROUND

Cytology smears and cytospin preparations are increasingly being used for molecular testing. With these limited samples, optimizing tissue extraction to maximize the DNA yield is, therefore, critical. This study examined 2 common methods of tissue extraction and compared DNA yields from different types of glass slides.

METHODS

The H226 lung cancer cell line and 5 clinical samples of cellular effusions were used to prepare Diff-Quik-stained cytospins on 4 types of glass slides: fully frosted (FF), nonfrosted (NF), positively charged (PC), and silane-coated (SC). Tissue extraction was performed by either scalpel-blade scraping or cell lifting with the Pinpoint Slide DNA Isolation System (Zymo Research). DNA was extracted with the QIAamp DNA Mini Kit (Qiagen) and was quantified with the Quant-iT PicoGreen Kit (Life Technologies).

RESULTS

The DNA yield in cell-line cytospins was significantly lower from FF slides versus NF, PC, and SC slides with both scraping and cell-lifting methods. In addition, scraping yielded significantly more DNA than cell lifting (P = .005). DNA yields from 5 clinical effusion cases with FF and NF slides showed results similar to the results for cell-line samples, with scraping consistently yielding more DNA than cell lifting and with NF slides outperforming FF slides.

CONCLUSIONS

Optimizing the DNA yield extracted from cytology specimens maximizes the chances of successful molecular testing and is critical in cases of low or marginal cellularity. This study demonstrates the following: 1) scraping yields more DNA than cell lifting, and 2) NF slides yield more DNA than FF slides.

Factors affecting the success of next-generation sequencing in cytology specimens

BACKGROUND

The use of cytology specimens for next-generation sequencing (NGS) is particularly challenging because of the unconventional substrate of smears and the often limited sample volume. An analysis of factors affecting NGS testing in cytologic samples may help to increase the frequency of successful testing.

METHODS

This study reviewed variables associated with all in-house cytology cases (n = 207) that were analyzed by NGS with the Ion Torrent platform during a 10-month interval. A statistical analysis was performed to measure the effects of the DNA input threshold, specimen preparation, slide type, tumor fraction, DNA yield, and cytopathologist bias.

RESULTS

One hundred sixty-four of 207 cases (79%) were successfully sequenced by NGS; 43 (21%) failed because of either a low DNA yield or a template/library preparation failure. The median estimated tumor fraction and DNA concentration for the successfully sequenced cases were 70% and 2.5 ng/μL, respectively, whereas they were 60% and 0.2 ng/μL, respectively, for NGS failures. Cell block sections were tested in 91 cases, and smears were used in 116 cases. NGS success positively correlated with the DNA yield but not the tumor fraction. Cell block preparations showed a higher success rate than smears. Frosted-tip slides yielded significantly more DNA than fully frosted slides. Lowering the input DNA concentration below the manufacturer's recommended threshold of 10 ng (>0.85 ng/μL) resulted in a marked increase in the NGS success rate from 58.6% to 89.8%.

CONCLUSIONS

The failure of NGS with cytology samples is usually a result of suboptimal DNA due to multiple pre-analytical factors. Knowledge of these factors will allow better selection of cytology material for mutational analysis.