Molecular testing in lung cancer: fine-needle aspiration specimen adequacy and test prioritization prior to the CAP/IASLC/AMP Molecular Testing Guideline publication

Sputum cell-free DNA for detection of alterations of multiple driver genes in lung adenocarcinoma

BACKGROUND

Sputum cell-free DNA (cfDNA) has been confirmed to be a valued surrogate sample for detection of EGFR mutations in patients with lung adenocarcinoma (LAC). Whether it is suitable for detection of mutations of multiple driver genes has not been reported.

METHODS

A total of 83 patients with LAC were enrolled and their sputum and paired tumor samples were collected. A next-generation sequencing (NGS)-based 10-gene panel was used to test sputum supernatant-derived cfDNA and paired tumor DNA. The sputum sediments were used for cytological evaluation.

RESULTS

The total positive rates of hotspot mutations of the 10 driver genes in sputum cfDNA and matched tissue samples were 65.1% and 77.1%, respectively. The overall detection sensitivity of variants in sputum cfDNA was 81.3% (95% confidence interval [CI], 69.2%, 89.5%) and the specificity was 100% (95% CI, 79.1%, 100%). The sensitivities of testing sputum cfDNA from patients with stage IIIB-IV was 87.0% (95% CI, 74.5%, 94.1%); the sensitivities of testing sputum cfDNA from patients with malignant sputum was 92.3% (95% CI, 78.0%, 98.0%); and the sensitivity of testing sputum cfDNA from patients with malignant sputum in stage IIIB-IV were 94.1% (95% CI, 78.9%, 99.0%).

CONCLUSIONS

This study demonstrated that sputum cfDNA were successfully used for the detection of multiple driver genes by NGS. Sputum cfDNA could be a valuable surrogate clinical sample for all-in-one test of mutations to guide target therapies, especially for patients with advanced LAC and malignant sputum.

Advances in cytology of lung cancer

Cytopathology has emerged as a promising platform in precision oncology especially after the revolutionary change in our understanding of the concept of lung cancer etiopathogenesis. With increasing use of minimally invasive techniques for sample acquisition, it becomes almost mandatory to utilize precious cytology samples maximally and judiciously by appropriate triaging of the specimen and timely action of the cytopathology team. Existing patient management protocols require accurate morphologic and molecular diagnosis of the lung cancer specimens which needs knowledge about evolving techniques related to specimen procurement, updates of genomic variants of lung cancer and recently developed molecular testing platforms and algorithms which are capable enough to use even miniscule amount of diagnostic material. This review provides a brief knowledge about advances in cytology of lung cancer which are helpful for developing correct clinical management strategies.

Making the most of small samples: Optimization of tissue allocation of pediatric solid tumors for clinical and research use

INTRODUCTION

Tissue from pediatric solid tumors is in high demand for use in high-impact research studies, making the allocation of tissue from an anatomic pathology laboratory challenging. We designed, implemented, and assessed an interdepartmental process to optimize tissue allocation of pediatric solid tumors for both clinical care and research.

METHODS

Oncologists, pathologists, surgeons, interventional radiologists, pathology technical staff, and clinical research coordinators participated in the workflow design. Procedures were created to address patient identification and consent, prioritization of protocols, electronic communication of requests, tissue preparation, and distribution. Pathologists were surveyed about the value of the new workflow.

RESULTS

Over a 5-year period, 644 pediatric solid tumor patients consented to one or more studies requesting archival or fresh tissue. Patients had a variety of tumor types, with many rare and singular diagnoses. Sixty-seven percent of 1768 research requests were fulfilled. Requests for archival tissue were fulfilled at a significantly higher rate than those for fresh tissue (P > .001), and requests from resection specimens were fulfilled at a significantly higher rate than those from biopsies (P > .0001). In an anonymous survey, seven of seven pathologists reported that the process had improved since the introduction of the electronic communication model.

CONCLUSIONS

A collaborative and informed model for tissue allocation is successful in distributing archival and fresh tissue for clinical research studies. Our workflows and policies have gained pathologists' approval and streamlined our processes. As clinical and research programs evolve, a thoughtful tissue allocation process will facilitate ongoing research.

Cytology Smears in the Era of Molecular Biomarkers in Non-Small Cell Lung Cancer: Doing More With Less

CONTEXT

- The rapid advances in targeted therapies in non-small cell lung cancer (NSCLC) make the optimization and implementation of cytology specimens for molecular testing a priority. Up to 70% of patients with NSCLC are diagnosed at advanced stages and tissue biopsies often cannot be taken. Although cytology samples provide high-quality material for molecular testing, molecular cytopathology is not yet well known or widely used.

OBJECTIVE

- To report the many advances in molecular cytopathology and the suitability and utility of cytology samples in molecular and genetic testing of NSCLC.

DATA SOURCES

- Data sources comprised published peer-reviewed literature and personal experience of the authors.

CONCLUSIONS

- Molecular testing can be performed on cytologic specimens, especially on direct smears. Rapid on-site evaluation by cytopathologists has improved the adequacy and the management of cytology samples for molecular testing. Mutational profiling of NSCLC using next-generation sequencing can be performed on cytology samples from very small amounts of DNA. Fluorescence in situ hybridization assays on cytology specimens, including stained direct smear, offer some distinct advantages over their histologic counterpart, and are used to detect ALK and ROS1 rearrangements in NSCLC. Cytology specimens allow assessment of the entire tumor cell nucleus, avoiding signal loss from truncation artifacts. The use of cytology samples for assessing programmed death ligand-1 protein expression is currently being developed. Protocols for bisulfite conversion and DNA droplet digital polymerase chain reaction assays have been optimized for cytology smear to investigate aberrant DNA methylation of several NSCLC-related genes.

The lonely driver or the orchestra of mutations? How next generation sequencing datasets contradict the concept of single driver checkpoint mutations in solid tumours - NSCLC as a scholarly example

Driver mutations are considered to be responsible for the majority of cancers and several of those mutations provide targets in order to set up personalized therapies. So far the generally accepted opinion had been that driver mutations occur as stand-alone factors, but novel sequencing technologies induced an essential rethink. Next generation sequencing approaches have shown that double, triple or multiple concurrent mutations could occur within the same tumour and may by interaction influence sensitivity to anticancer drugs and therapy success. This review focusses on this novel concept and discusses the challenges for molecular pathology and laboratory diagnostics while providing putative solutions to overcome the present pitfalls, thereby taking NSCLC as an example.

Cytology smears for DNA extraction: Practical approach for selecting the best slide

BACKGROUND

Next generation sequencing (NGS) to detect actionable genetic abnormalities is standard of care in advanced stage lung adenocarcinoma. Many studies have shown that the molecular results obtained from fine needle aspiration cytology material are comparable to those obtained from formalin-fixed tissue samples. We undertook this study to validate DNA extraction from cytology material for molecular studies and to find any correlation between DNA yield, pattern of tumour cells and tumour fraction.

METHODS

DNA was extracted from 34 cytology slides of pulmonary adenocarcinoma cases with predetermined EGFR mutation status. Cytology slides were reviewed for pattern of tumour distribution and tumour fraction. NGS was performed on five slides with variable DNA and compared with original results.

RESULTS

There were 14 alcohol-fixed and 20 air-dried smears. The mean DNA yield was 1.74 μg and median of 0.4 μg (range, 0.02-21 μg). Tumour fractions varied from 10% to 90%. No correlation was found between tumour fraction and DNA yield (P = 0.14). The mean DNA yield was high in slides with tumour throughout the slide (sheets or scattered clusters) as compared to rare scattered clusters and/or single cells. EGFR mutation was found in four of the five cases sent for NGS lung panel while one case revealed BRAF mutation.

CONCLUSIONS

DNA with good quantity and quality can be extracted from the cytology slides for NGS irrespective of type of fixation. DNA yield has better correlation with distribution pattern of tumour cells on the slides rather than tumour fraction.

Molecular classification of cancer with the 92-gene assay in cytology and limited tissue samples

BACKGROUND

Detailed molecular evaluation of cytology and limited tissue samples is increasingly becoming the standard for cancer care. Reproducible and accurate diagnostic approaches with reduced demands on cellularity are an ongoing unmet need. This study evaluated the performance of a 92-gene assay for molecular diagnosis of tumor type/subtype in cytology and limited tissue samples.

METHODS

Clinical validation of accuracy for the 92-gene assay in limited tissue samples such as cytology cell blocks, core biopsies and small excisions was conducted in a blinded multi-institutional study (N = 109, 48% metastatic, 53% grade II and III). Analytical success rate and diagnostic utility were evaluated in a consecutive series of 644 cytology cases submitted for clinical testing.

RESULTS

The 92-gene assay demonstrated 91% sensitivity (95% CI [0.84, 0.95]) for tumor classification, with high accuracy maintained irrespective of specimen type (100%, 92%, and 86% in FNA/cytology cell blocks, core biopsies, and small excisions, respectively; p = 0.26). The assay performed equally well for metastatic versus primary tumors (90% vs 93%, p = 0.73), and across histologic grades (100%, 90%, 89%, in grades I, II, and III, respectively; p = 0.75). In the clinical case series, a molecular diagnosis was reported in 87% of the 644 samples, identifying 23 different tumor types and allowing for additional mutational analysis in selected cases.

CONCLUSIONS

These findings demonstrate high accuracy and analytical success rate of the 92-gene assay, supporting its utility in the molecular diagnosis of cancer for specimens with limited tissue.

Plasma genotyping in patients with non-small-cell lung cancer: simplifying or confusing the diagnosis?

The identification of driver mutations in patients with advanced non-small-cell lung cancer has changed the treatment outcomes for patients with actionable driver mutations. Lack of tissue at diagnosis, however, remains a central obstacle in making optimal treatment decisions in patients with advanced disease. Although the US FDA has approved one plasma-based test for detecting epidermal growth factor receptor mutations in patients with advanced stage disease, sensitivity of these assays remains mediocre, necessitating additional tissue testing and possible delays in patients with negative results. Serial monitoring for response and early detection of acquired resistance to targeted therapies is also possible with cell-free DNA, however the benefit of switching therapy prior to detection of changes on imaging is unknown currently.

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.

Helical-Tip Needle for Transthoracic Percutaneous Image-Guided Biopsy of Lung Tumors: Results of a Pilot Prospective Comparative Study with a Standard Tru-Cut Needle

PURPOSE

To prospectively evaluate feasibility and diagnostic performance of the 14-gauge helical-tip (Spirotome™, Cook^® Medical, Bloomington, USA) needle in transthoracic needle biopsy (TTNB) of lung lesions, compared to a conventional 18-gauge Tru-Cut needle.

MATERIALS AND METHODS

Study was institutional review board approved, with informed consent obtained. Data from synchronous Spirotome and Tru-Cut image-guided TTNB of 20 consecutive patients with malignant peripheral lung tumors larger than 3 cm were enrolled for pathologic characterization and mutational analysis. Samples obtained with Spirotome and Tru-Cut needle were compared for fragmentation, length, weight, morphologic and immunohistochemistry typifying, tumor cellularity (TC) and DNA concentration.

RESULTS

The technical success rate for TTNB with Spirotome was 100%, and no major complications occurred. Less fragmentation (mean 2 vs. 3 fragments, P = .418), greater weight (mean 13 vs. 8.5 mg, P = .027) and lower length (mean 10.2 vs. 12.6 mm, P = .174) were observed with Spirotome compared to Tru-Cut needle. Accuracy of Spirotome and Tru-Cut needle in defining cancer histotype was similar (90%). Absolute and relative TC (mean 42 vs. 38, 124 vs. 108/10HPF), and DNA concentration (mean 49.6 vs. 39.0 ng/μl) were higher with Spirotome compared to Tru-Cut needle, with no statistical significance (P = .787 and P = .140, respectively).

CONCLUSIONS

Percutaneous 14-gauge Spirotome TTNB of selected lesions is feasible and accurate. It provides adequate samples for diagnosis, comparable to 18-gauge Tru-Cut needle, with a higher amount of tumor tissue (weight, TC, DNA concentration) even in shorter samples.

Sample types applied for molecular diagnosis of therapeutic management of advanced non-small cell lung cancer in the precision medicine

In this era of precision medicine, molecular biology is becoming increasingly significant for the diagnosis and therapeutic management of non-small cell lung cancer. The specimen as the primary element of the whole testing flow is particularly important for maintaining the accuracy of gene alteration testing. Presently, the main sample types applied in routine diagnosis are tissue and cytology biopsies. Liquid biopsies are considered as the most promising alternatives when tissue and cytology samples are not available. Each sample type possesses its own strengths and weaknesses, pertaining to the disparity of sampling, preparation and preservation procedures, the heterogeneity of inter- or intratumors, the tumor cellularity (percentage and number of tumor cells) of specimens, etc., and none of them can individually be a “one size to fit all”. Therefore, in this review, we summarized the strengths and weaknesses of different sample types that are widely used in clinical practice, offered solutions to reduce the negative impact of the samples and proposed an optimized strategy for choice of samples during the entire diagnostic course. We hope to provide valuable information to laboratories for choosing optimal clinical specimens to achieve comprehensive functional genomic landscapes and formulate individually tailored treatment plans for NSCLC patients that are in advanced stages.

Molecular testing of different cytologic preparations in patients with advanced lung adenocarcinoma: which yields the best results?

INTRODUCTION

This study constitutes the first systematic comparison of molecular results between different cytology preparations in patients with lung adenocarcinoma undergoing testing for EGFR, KRAS, and BRAF mutations.

MATERIALS AND METHODS

115 archival cytology preparations (direct smears, ThinPrep preparations [TP], and cell blocks [CB]) from lung adenocarcinomas with known EGFR, KRAS, or BRAF mutations were tested and compared with clinical testing results. Results were compared between preparations and analyzed in relation to tumor purity and tumor cell content.

RESULTS

82 (77%) of 106 informative cases were concordant with clinical testing results. There was no significant difference in the concordance rate between CB, TP, air-dried smears, or alcohol-fixed smears (P = 0.3803), nor between preparations with <25%, 25% to 50%, or >50% tumor purity (P = 0.1147). Concordance rates were lower in preparations with ≤100 tumor cells (P = 0.0002).

CONCLUSIONS

Smears, TP, and CB are all valid substrates for molecular testing. Although tumor purity did not significantly affect results, low tumor content showed poorer performance. Recording tumor purity and content is recommended.

The feasibility of molecular testing on cell blocks created from brush tip washings in the assessment of peripheral lung lesions

BACKGROUND

With the rapid development of genotype-guided therapies, molecular testing is becoming important in the management of lung cancer. Bronchoscopy is one of the most common investigations performed to diagnose and investigate lung cancer. Given the limited samples often produced by bronchoscopy, this study aims to evaluate the feasibility of performing molecular testing on cell blocks created from bronchoscope cytology brush tip washings (BTW).

METHODS

Patients with positive brush cytology for tumour cells had cell blocks created from the BTW. Mutations were detected using amplicon-based massively parallel sequencing of targeted regions of EGFR, KRAS, and BRAF genes.

RESULTS

A total of 45 patients were included in this study. Of those, 91% had adequate specimens for molecular analysis and 66% of patients with adenocarcinoma had mutations detected. Bronchial brush tip wash cell blocks were the sole specimen available for molecular testing in 27 (60%) patients.

CONCLUSIONS

The findings of this study demonstrate that molecular testing can be performed on cell blocks created from BTW and this technique may allow for an increase in bronchoscope specimens amenable to molecular testing without further increasing morbidity and mortality.

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

The Papanicolaou Society of Cytopathology has developed a set of guidelines for respiratory cytology including indications for sputum examination, bronchial washings and brushings, CT-guided FNA and endobronchial ultrasound guided fine needle aspiration (EBUS-FNA), as well as recommendations for classification and criteria, ancillary testing and post-cytologic diagnosis management and follow-up. All recommendation documents are based on the expertise of committee members, an extensive literature review, and feedback from presentations at national and international conferences. The guideline documents selectively present the results of these discussions. The present document summarizes recommendations for ancillary testing of cytologic samples. Ancillary testing including microbiologic, immunocytochemical, flow cytometric, and molecular testing, including next-generation sequencing are discussed. Diagn. Cytopathol. 2016;44:1000-1009. © 2016 Wiley Periodicals, Inc.

Rapid removal of cytology slide coverslips for DNA and RNA isolation

INTRODUCTION

Because of consistent demand for identification of molecular targets for diagnosis and treatment, ancillary tests are increasingly being developed for cytology specimens. One time-consuming step in this procedure is glass coverslip removal by xylene. Here we describe a method for rapid coverslip removal using liquid nitrogen.

MATERIALS AND METHODS

Direct smears were prepared from residual pleural fluid, Diff-Quik stained, then covered with a glass coverslip. Coverslips were then removed by either immersing the slides in xylene for 3 to 4 days, or by a razor blade after rapidly freezing the slides in liquid nitrogen. The DNA or RNA was extracted, and the quantities of DNA and RNA were evaluated. The amplifiability of the DNA and RNA was also evaluated by real-time polymerase chain reaction (PCR) and real time reverse transcription (RT)-PCR.

RESULTS

The concentrations of DNA isolated using the two procedures are not significantly different (2.79 μg/mL with liquid nitrogen method versus 2.56 μg/mL with xylene method, n = 5). Similar results were observed for RNA concentration (13.28 μg/mL versus 12.22 μg/mL). The DNA extracted from the two procedures can be amplified without significant difference. Similar results were obtained from real time RT-PCR for RNA samples.

CONCLUSIONS

By removing the coverslip from the cytology slides using the liquid nitrogen method, DNA and RNA can be extracted from the slides without affecting the quantity and quality of the nucleic acids, and is equivalent to the xylene coverslip removal method.

EGFR mutation testing using archival-stained smears in non-small cell lung carcinoma

OBJECTIVE

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have shown benefits regarding progression-free and overall survival in patients whose tumours show EGFR mutations. Most patients' lung cancer is metastatic when detected. Small tissue samples and cytological materials are widely used in diagnosis. The aim of the present study was to compare the EGFR mutation analysis results between cytology, small biopsies and resections.

METHODS

Archival material for EGFR testing was reviewed. Cell blocks and/or stained smears and tissue blocks were used where appropriate. The tumour cell count and percentage were recorded as well as the DNA content. The influence of TTF-1 immunoreactivity on EGFR testing was also investigated.

RESULTS

The study cohort included 300 unpaired specimens of 84 resections, 83 small biopsies and 133 cytological materials. EGFR mutation rates did not differ significantly for cytology, small biopsy and resections (P > 0.05). The higher tumour cell percentage in FNAs than in exfoliative cytology did not affect the EGFR mutation status. EGFR mutation rates were similar when either slides or cell blocks were used. Cytology slides revealed a higher tumour cell content and DNA concentration than the cell blocks. May-Grünwald-Giemsa (MGG)-stained smears had higher rates of the EGFR mutation than the Papanicolaou (Pap)-stained slides (P < 0.05). Tumours with negative immunoreactivity for TTF-1 are less likely to have an EGFR mutation (P < 0.05).

CONCLUSIONS

Cytological materials can be used successfully for mutation analysis in lung cancer.

Quantitative assessment of cell block cellularity and correlation with molecular testing adequacy in lung cancer

INTRODUCTION

Determination of fine-needle aspiration (FNA) material adequacy is essential prior to performing molecular testing (MT) in order to ensure good results and maximize resources. This study investigates several quantitative measures of cellularity in FNA samples of lung carcinoma, and correlates the results with MT adequacy.

MATERIALS AND METHODS

A blinded retrospective analysis of 20 non-small-cell lung carcinoma cases was conducted: 13 contained "sufficient" material for EGFR/KRAS sequencing and ALK FISH studies; and 7 contained "insufficient" material for these tests. Three 400x fields-of-view (FOVs) were analyzed from digitized cell block glass slides of these cases. Cellularity in these FOVs was quantified using three methods: (1) visual estimation by cytopathologist; (2) manually annotated contours (MACs); (3) software derived, manually adjusted contours (SDMACs) using a custom segmentation script with adjustable parameters. These methods were evaluated using the Mann-Whitney-Wilcoxon test, paired t test, and receiver operating characteristic/area under the curve (AUC) analysis.

RESULTS

There were significant differences between the insufficient/sufficient groups for each estimation method (visual P < 0.05, MAC P < 0.05, SDMAC P < 0.01). Variation of mean values was highest in the visual estimation method. AUC values were visual estimation = 0.903, MAC = 0.903, and SDMAC = 0.958. Mean variation of the 3 FOV values was found to be significantly higher for visual estimation compared with the other methods.

CONCLUSION

Quantitative analysis of cellularity in digitized cell block material is feasible using different methods. In this investigation, the SDMAC method provided the highest accuracy and lowest variability. This supports image analysis as an objective and quantitative tool to assess FNA sample adequacy for guiding supplemental MT.

Longitudinal molecular characterization of endoscopic specimens from colorectal lesions

AIM: To compare molecular profiles of proximal colon, distal colon and rectum in large adenomas, early and late carcinomas. To assess feasibility of testing directed at molecular markers from this study in routine clinical practice.

METHODS: A prospective 3-year study has resulted in the acquisition of samples from 159 large adenomas and 138 carcinomas along with associated clinical parameters including localization, grade and histological type for adenomas and localization and stage for carcinomas. A complex molecular phenotyping has been performed using multiplex ligation-dependent probe amplification technique for the evaluation of CpG-island methylator phenotype (CIMP), PCR fragment analysis for detection of microsatellite instability and denaturing capillary electrophoresis for sensitive detection of somatic mutations in KRAS, BRAF, TP53 and APC genes.

RESULTS: Molecular types according to previously introduced Jass classification have been evaluated for large adenomas and early and late carcinomas. An increase in CIMP+ type, eventually accompanied with KRAS mutations, was notable between large adenomas and early carcinomas. As expected, the longitudinal observations revealed a correlation of the CIMP+/BRAF+ type with proximal location.

CONCLUSION: Prospective molecular classification of tissue specimens is feasible in routine endoscopy practice. Increased frequency of some molecular types corresponds to the developmental stages of colorectal tumors. As expected, a clear distinction is notable for tumors located in proximal colon supposedly arising from the serrated (methylation) pathway.

Destaining of Diff-Quik stained cytologic smears is not necessary for the detection of anaplastic lymphoma kinase gene rearrangement in lung adenocarcinoma by fluorescence in situ hybridization

Background:

Anaplastic lymphoma kinase (ALK) gene rearrangement analysis by fluorescence in situ hybridization (FISH) is one of the standard molecular tests for targeted therapy of lung adenocarcinoma. However, insufficient cell block cellularity may impede molecular testing. A recent study showed that Diff-Quik (DQ) stained cytology smear is suitable for ALK by FISH.

Aims:

The aim of our study was to observe the impact of destaining intervals on the quality of FISH signals and determine if DQ smears without destaining would allow FISH analysis.

Materials and Methods:

Thirty-five DQ smears from 27 cases of lung adenocarcinoma were analyzed for ALK gene rearrangement by FISH. Twenty three DQ smears were destained for different intervals, including 30 s (13 cases), 1 min (6 cases), or 2 min (4 cases). Twelve DQ smears were not subjected to destaining. For further validation, FISH signals in 8 smears and 6 cell blocks were compared with the paired destained DQ smears. The signal quality was semi-quantified and analyzed with Chi-squared test.

Results:

Of the total 27 selected cases, three (11%) were positive for ALK gene rearrangement, whereas 24 (89%) were negative. FISH signal was satisfactory in all DQ smears. There was no significant difference in the quality of signal among smears with different destaining intervals (P = 0.55) or between smears with and without destaining (P = 0.41). DQ smears without destaining showed identical FISH results and similar or better signals as compared with paired destained smears and cell blocks in all cases.

Conclusions:

Duration of destaining intervals does not impact the quality of FISH signal on DQ smears. Destaining of DQ smears is not necessary for ALK by FISH.

Randomized Trial of Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration With and Without Rapid On-site Evaluation for Lung Cancer Genotyping

BACKGROUND

Experts and scientific society guidelines recommend that rapid on-site evaluation (ROSE) be used with endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) to optimize lung cancer genotyping, but no comparative trial has been carried out to confirm and quantify its usefulness.

METHODS

To assess the influence of ROSE on the yield of EBUS-TBNA for a multigene molecular analysis of lung cancer samples, consecutive patients with suspected or known advanced lung cancer were randomized to undergo EBUS-TBNA without ROSE (EBUS arm) or with ROSE (ROSE arm). The primary end point was the rate of the successful accomplishment of the institution's clinical protocol for molecular profiling of nonsquamous non-small cell lung cancer (EGFR and KRAS testing, followed by ALK testing for tumors with EGFR and KRAS wild-type status).

RESULTS

Complete genotyping was achieved in 108 of 126 patients (85.7%) (90.8% in the ROSE arm vs 80.3% in the EBUS arm, P = .09). The patients in the ROSE arm were less likely to have samples that could be used only for pathologic diagnosis because of minimal tumor burden (0 vs 6, P = .05), and were more likely to have the bronchoscopy terminated after a single biopsy site (58.9% vs 44.1%, P = .01).

CONCLUSIONS

ROSE prevents the need for a repeat invasive diagnostic procedure aimed at molecular profiling in at least one out of 10 patients with advanced lung cancer and significantly reduces the risk of retrieving samples that can be used only for pathologic subtyping because of minimal tumor burden.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01799382; URL: www.clinicaltrials.gov.

Preanalytic parameters in epidermal growth factor receptor mutation testing for non-small cell lung carcinoma: A review of cytologic series

The results from molecular assays can be affected significantly by the preanalytic condition of cytologic samples. The authors review current knowledge on the use of cytologic samples for epidermal growth factor receptor (EGFR) mutation testing in non–small cell lung cancer with a focus on preanalytic parameters. A systematic electronic search of the MEDLINE database was performed to identify original articles that reported the use of cytologic samples for EGFR molecular analysis and included a minimum of 100 samples. The information collected included author(s), journal, and year of publication; number of patients and samples; sampling method; type of preparation; type of fixative; staining techniques; mutation analysis techniques; tumor cellularity; the percentage of tumor cells; data on DNA quantity, quality, and concentration; failed assays; and the mutation rate. EGFR mutation analysis was conducted on 4999 cytologic samples from 22 studies that fulfilled the inclusion criteria. Fine‐needle aspirates and pleural effusions were the most common types of specimens used. DNA was mainly extracted from cell blocks and smears, and the most commonly reported fixatives included formalin, ethanol, and CytoLyt. Cellularity assessments and DNA yields were available from 5 studies each. The average success rate for the assays that used cytologic specimens was 95.87% (range, 85.2%‐100%). The mutation rate ranged from 6% to 50.46%, and a higher mutation detection rate and lower numbers of insufficient cases were reported for pleural effusions and lymph node samples from endobronchial ultrasound‐guided transbronchial needle aspiration compared with histologic specimens. Low cellularity and a low percentage of tumor cells were associated with higher test failure rates. Future guidelines should consider the current data for specific recommendations regarding cytologic samples. Cancer (Cancer Cytopathol) 2015;123:633–643. © 2015 American Cancer Society.

Preanalytic parameters for epidermal growth factor receptor mutation testing are reviewed in non–small cell lung cancer using 4999 cytologic samples from 22 studies. A higher mutation detection rate and lower numbers of insufficient cases are observed for pleural effusions and lymph node samples obtained using endobronchial ultrasound‐guided transbronchial needle aspiration compared with histologic specimens, and low cellularity and a lower percentage of tumor cells are associated with higher test failure rates. Future guidelines should consider the current data for specific recommendations regarding cytologic samples.

Poor cell block adequacy rate for molecular testing improved with the addition of Diff-Quik-stained smears: Need for better cell block processing

BACKGROUND

In the era of personalized medicine, requests for molecular testing of specimens obtained with minimally invasive procedures such as fine-needle aspiration have been increasing. Although cell blocks (CBs) are the recommended specimens for molecular testing, their performance has not been well analyzed. The objective of this study was to assess the frequency and types of samples deemed unsatisfactory for molecular testing (quantity not sufficient [QNS]).

METHODS

One year after the implementation of careful monitoring of QNS cases, cases submitted for lung cancer molecular testing were analyzed for the QNS rate. When the cases were rejected for the inadequacy of CBs of cytology specimens, air-dried, Diff-Quik (DQ)-stained smears were reviewed and used if they were adequate. The QNS rates were compared across 4 specimen categories: large resection, small biopsy, CB alone, and CB with DQ smears.

RESULTS

One hundred seventy-six cases were studied, and 45 (25.6%) were unsatisfactory. Only 1 of 73 large resection specimens was rejected because of decalcification. The QNS rate for small biopsy specimens was 35.9% (28 of 78), whereas 64% (16 of 25) of cytology cases ordered on CBs were rejected. In combination with DQ smears, the QNS rate of cytology specimens was 32% (8 of 25), which was a significant improvement over CBs only (P = .024) and was not significantly different from the QNS rate for small biopsies (P = .671).

CONCLUSIONS

The utilization of DQ-stained smears for molecular testing improves the adequacy of cytologic samples and provides a minimally invasive alternative to surgical biopsy when molecular analysis of tumor material is necessary.

Minimal requirements for the molecular testing of lung cancer

From the aspect of the contemporary pathologic diagnostics of lung cancer, it is a key issue of the tissue obtained since small biopsies and cytology still play a major role. In the non-small cell lung cancer era, cytology considered equal to biopsy. However, in recent years it is unable to provide quality diagnosis and must be replaced by biopsy. Various molecular techniques can handle various different tissue samples which must be considered during molecular pathology diagnosis. Besides, tumor cell-normal cell ratio in the obtained tissue as well as the absolute tumor cell number have great significance whose information must be provided in the primary lung cancer diagnosis. Last but not least, for continuous sustainable molecular diagnostics of lung cancer rational algorythms, affordable technology and appropriate reimbursement are equally necessary.

Kinomic profiling of electromagnetic navigational bronchoscopy specimens: a new approach for personalized medicine

Purpose

Researchers are currently seeking relevant lung cancer biomarkers in order to make informed decisions regarding therapeutic selection for patients in so-called “precision medicine.” However, there are challenges to obtaining adequate lung cancer tissue for molecular analyses. Furthermore, current molecular testing of tumors at the genomic or transcriptomic level are very indirect measures of biological response to a drug, particularly for small molecule inhibitors that target kinases. Kinase activity profiling is therefore theorized to be more reflective of invivo biology than many current molecular analysis techniques. As a result, this study seeks to prove the feasibility of combining a novel minimally invasive biopsy technique that expands the number of lesions amenable for biopsy with subsequent exvivo kinase activity analysis.

Methods

Eight patients with lung lesions of varying location and size were biopsied using the novel electromagnetic navigational bronchoscopy (ENB) technique. Basal kinase activity (kinomic) profiles and exvivo interrogation of samples in combination with tyrosine kinase inhibitors erlotinib, crizotinib, and lapatinib were performed by PamStation 12 microarray analysis.

Results

Kinomic profiling qualitatively identified patient specific kinase activity profiles as well as patient and drug specific changes in kinase activity profiles following exposure to inhibitor. Thus, the study has verified the feasibility of ENB as a method for obtaining tissue in adequate quantities for kinomic analysis and has demonstrated the possible use of this tissue acquisition and analysis technique as a method for future study of lung cancer biomarkers.

Conclusions

We demonstrate the feasibility of using ENB-derived biopsies to perform kinase activity assessment in lung cancer patients.