Oncomine Dx Research Articles

Transcriptome amplification and fusion gene detection using ultra-trace cells derived from cytology specimens

Tumours are complex and despite scientific breakthroughs, there is much to be elucidated about cancer and its mechanisms. By personalising treatment, outcomes can be improved and genetic analysis is key to this as it allows genetic alterations to be identified and treatment to be precisely targeted. Dr Kenji Amemiya is a cytotechnologist and Chief Clinical Laboratory Technician at the Yamanashi Prefectural Central Hospital Genome Analysis Center (GAC). He is working to better understand the complex inner landscape of cancer and therefore improve cancer detection, diagnosis and treatment. Formalin‐fixed paraffin‐embedded (FFPE) specimens are typically used for genetic testing but there are drawbacks to this, including the FFPE DNA becoming damaged during the fixation process with formalin, resulting in low quality and quantity of DNA. Amemiya is collaborating closely with Chairman of the GAC, Professor Emeritus Masao Omata. They are interested in the use of cytology samples instead of tissue samples in genome analysis, as a less invasive method. Survival rates are increased when genomic analysis is utilised in non-small cell lung cancer (NSCLC). In one project, Amemiya, Omata and the team explored the potential of performing NGS analysis with archived cytological specimens (ACSs). They utilised an integrated NGS platform called the Oncomine Dx Target Test Multi-CDx system to compare the quantity and quality of extracted nucleic acids, the sequencing quality control (QC) and the detected variants between ACSs and FFPE tissues. They found that the RNA integrity was higher in ACSs and there was no difference in sequencing results, compared with FFPE tissues.

EP.06F.02 Enhancing Clinical Utility: Oncomine Dx Target Test Augments Biomarker Detection in Advanced Non-Small-Cell Lung Cancer

EP.06F.02 Enhancing Clinical Utility: Oncomine Dx Target Test Augments Biomarker Detection in Advanced Non-Small-Cell Lung Cancer

Analytical and Clinical Validation of the Oncomine Dx Target Test to Assess HER2 Mutation Status in Tumor Tissue Samples From Patients With Non–Small Cell Lung Cancer Treated With Trastuzumab Deruxtecan in the DESTINY-Lung01 and DESTINY-Lung02 Studies

Context.— Trastuzumab deruxtecan (T-DXd), a human epidermal growth factor receptor 2 (HER2)–targeted therapy, has demonstrated durable anticancer activity in patients with advanced, metastatic HER2 (also known as ERBB2)–mutant (HER2m) non–small cell lung cancer (NSCLC) who have limited treatment options and poor prognosis. Objective.— To analytically validate and assess the clinical utility of the Oncomine Dx Target (ODxT) Test as a companion diagnostic to identify patients with HER2m NSCLC. Design.— Tumor samples from patients in DESTINY-Lung01 and DESTINY-Lung02 were retrospectively analyzed alongside commercially procured samples using the ODxT test and compared to the assays used for screening in these clinical trials. Results.— Positive percent agreement (PPA) and negative percent agreement (NPA) between the ODxT Test and TruSight Tumor 170 assay when testing DESTINY-Lung01 and commercially procured samples met prespecified thresholds (PPA and NPA ≥90%) for analytical accuracy (100% and 99.1%). The ODxT Test results were highly concordant with clinical trial assays (CTAs) used in DESTINY-Lung01 (PPA and NPA, 98.0% and 100%) and DESTINY-Lung02 (PPA and NPA, 96.7% and 100%) to identify activating HER2 mutations in tumor samples. Confirmed objective response rates were similar between patients with HER2m tumors identified by the ODxT Test and by CTAs in DESTINY-Lung01 (58.3% and 54.9%) and DESTINY-Lung02 (53.6% and 53.8%). Response duration was 12.0 and 9.3 months for patients identified by the ODxT Test and CTAs, respectively, in DESTINY-Lung01. Conclusions.— The ODxT Test detected HER2 mutations in NSCLC with high analytical and clinical accuracy and identified HER2m populations with response rates similar to populations identified by CTAs, supporting clinical utility of the ODxT Test to inform treatment decisions for HER2m NSCLC.

Comparison of diagnostic performance between Oncomine Dx target test and AmoyDx panel for detecting actionable mutations in lung cancer

Companion diagnostic (CDx) tests play important roles in identifying oncogenic driver genes and tailoring effective molecularly targeted therapies for lung cancer patients. In Japan, the Oncomine Dx target test (ODxTT) and the AmoyDx pan lung cancer PCR panel (AmoyDx) are prominent CDx tests and only one of these tests is covered by the domestic insurance system. However, these CDx tests cover different target regions and apply different technologies (ODxTT is amplicon-based next-generation sequencing and AmoyDx is multiplex PCR-based assay), which may lead to missing of actionable mutations affecting patient prognosis. Here, we performed a direct comparison analysis of 1059 genetic alterations of eight driver genes from 131 samples and evaluated the concordance between two CDx tests for detecting actionable variants and fusions. When excluding the eight uncovered variants (ODxTT: two variants, AmoyDx: six variants), the overall percent agreement was 97.6% (1026/1051) with 89.0% of overall positive percent agreement (89/100) and 98.5% of overall negative percent agreement (937/951). Of the 25 discordant genetic alterations, two were undetected despite being covered in the AmoyDx (one EGFR variant and one ROS1 fusion). Furthermore, there were potential false positives in the ODxTT (nine MET exon 14 skippings) and in the AmoyDx (five variants, six ROS1 and three RET fusions). These potential false positives in the AmoyDx likely due to non-specific amplification, which was validated by the unique molecular barcoding sequencing. The ODxTT missed two uncovered EGFR rare variants, which was visually confirmed in the raw sequencing data. Our study provides insights into real-world performance of CDx tests for lung cancer and ensures reliability to advance precision medicine.

Detection of EGFR exon 20 insertion mutations in non-small cell lung cancer: implications for consistent nomenclature in precision medicine

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations (E20ins) are the third most frequent mutations observed in non-small cell lung cancer, accounting for approximately 1-10% of all EGFR mutations. In the era of precision medicine and targeted therapies, consistent naming of genetic alterations is crucial to avoid confusion and errors. However, the annotation of EGFR E20ins mutations has been inconsistent, leading to confusion in the scientific literature and product documentation. In this study, our primary objective was to investigate the usage of different annotation related to EGFR E20ins in independent studies. Additionally, we assessed the distribution of EGFR E20ins mutations and estimated the detection coverage expected from each available EGFR E20ins detection assay. A total of 1,418 EGFR E20ins mutations were collected from six studies (FoundationInsights, Geneseeq Technology Inc, mobocertinib phase I/II trial, poziotinib phase II trial, sunvozertinib phase I trial, and Samsung Medical Center) and reorganised according to Human Genome Variation Society (HGVS) nomenclature. Our analysis revealed that the majority of EGFR E20ins mutations requiring correction were 'insertion' or 'deletion-insertion', which should be appropriately designated as 'duplication'. Additionally, duplicated variants were reported using different annotations in each study, and furthermore, even identical variant sequences were annotated differently within the same study. In all six studies, p.A767_V769dup and p.S768_D770dup were the most frequently observed EGFR E20ins. The Oncomine Dx Target Test showed the highest patient coverage at 77.2%, followed by the Droplex EGFR Mutation Test v2 with a patient coverage of 70.5% for EGFR E20ins patients. To ensure comprehensive coverage in real-world settings, it is essential to standardise the annotations for each variant, for example using the HGVS nomenclature. The accurate classification and analysis of drug responsiveness in EGFR E20ins necessitate consideration of the nomenclature, particularly with respect to the locations where the actual mutations occur.

Brief Report: Tepotinib as a Treatment Option in MET Exon 14 Skipping-Positive Lung Cancers—Investigating Discordance Between ArcherMET and the Oncomine Dx Target Test

IntroductionNSCLC is a leading cause of cancer-related mortality worldwide. Specific genetic alterations, such as MET exon 14 (METex14) skipping, have been identified in NSCLC, allowing targeted therapy. Tepotinib, a highly selective MET inhibitor, has displayed promise in patients with advanced NSCLC. Nevertheless, challenges arise when identifying treatment strategies for patients with discordant results regarding METex14 skipping detection between diagnostic tests. MethodsWe investigated patients with NSCLC and discordant results for METex14 skipping between the Oncomine Dx Target Test (ODxTT) and ArcherMET. Clinical response, adverse events, and the duration of tepotinib treatment were assessed, and statistical analysis was performed. ResultsAmong the 19 patients deemed METex14 skipping positive by ODxTT, only 10 had concordant results with ArcherMET. The number of METex14 skipping reads detected by ODxTT was significantly lower in discordant cases. Of the 19 patients, 14 received tepotinib, and comparable response and disease control rates were observed in both concordant and discordant cases. The duration of treatment did not significantly differ between the two groups. ConclusionsOur findings suggest that tepotinib has comparable therapeutic effects in patients with METex14 skipping-positive NSCLC irrespective of the concordance of results between ODxTT and ArcherMET. Tepotinib is a possible treatment option for patients with METex14 skipping, even in patients with discordant test results.

The Current Achievements of Multi-Gene Panel Tests in Clinical Settings for Patients with Non-Small-Cell Lung Cancer.

Some multi-gene panel tests have been implemented in clinical settings to guide targeted therapy in non-small-cell lung cancer (NSCLC) in Japan. The current performance of multi-gene panel tests under the condition that the Oncomine Dx Target Test (ODxTT) and Amoy Dx® Pan Lung Cancer PCR panel (AmoyDx-multi) are available remains relatively unknown. We retrospectively reviewed consecutive patients with NSCLC, whose FFPE samples were considered for genetic testing. We assessed the submission rates, the success rates, and the driver oncogene detection rates of multi-gene panel tests. A total of 225 patients were histologically newly diagnosed with NSCLC or diagnosed with a recurrence of NSCLC without a previous multi-gene panel test at our institution. Among the 225 patients, the FFPE samples of 212 patients (94.2%) were submitted for multi-gene panel testing, including 191 samples (84.9%) for the ODxTT and 21 samples (9.3%) for the AmoyDx-multi. Among the 212 samples submitted to multi-gene panel tests, the success rate was 99.5% (211/212). The detection rate of driver oncogene alterations for all histologies was 52.4% (111/212), and that for adenocarcinoma was 69.7% (106/152). A favorable submission rate and success rate of multi-gene panel tests were shown, along with a favorable detection rate in recent clinical settings.

Selpercatinib for treating recurrent mixed medullary and follicular cell-derived thyroid carcinoma: a case report

BackgroundMixed medullary and follicular cell-derived thyroid carcinoma (MMFCC) is characterized by the coexistence of follicular and C cell–derived tumour cell populations within the same lesion. Due to its rarity, its etiology and clinical course remain unclear, and treatment for advanced or recurrent cases has not been established.Case presentationWe report a case of MMFCC treated with selpercatinib. The patient was a 69-year-old male presenting with tumors in the right thyroid lobe and in the upper mediastinum. Fine-needle aspiration (FNA) cytology of the right thyroid lobe tumor revealed a medullary carcinoma; germline RET mutations were not detected. After resection of the right thyroid lobe with central node dissection, rapid intraoperative diagnosis of the mediastinal mass confirmed malignancy, leading to total thyroidectomy with excision of the upper mediastinal tumor. Histologically, the tumor in the right thyroid lobe and the pretracheal lymph node revealed a mixture of medullary and follicular carcinoma components, diagnosed as MMFCC. The mediastinal lymph node exhibited only medullary carcinoma components. At 11 months postoperatively, computed tomography scans showed enlargement of the right supraclavicular and upper mediastinal lymph nodes. FNA cytology of the right supraclavicular lymph node suggested the recurrence of medullary thyroid carcinoma. The gene panel testing (The Oncomine Dx Target Test Multi-CDx system®, Thermo Fisher SCIENTIFIC) of metastatic lymph node revealed RET somatic mutation (M918T). Treatment with selpercatinib was initiated, and both the cervical and mediastinal lymph nodes showed a reduction in size.ConclusionsWe report a rare case of selpercatinib use for MMFCC. Since RET mutations may occur frequently in MMFCC, selpercatinib could be effective in treating MMFCC.

Comparison between next-generation sequencing and multiplex polymerase chain reaction assays for nonsmall-cell lung cancer molecular diagnosis.

Genetic mutation detection has become an important step in nonsmall-cell lung cancer (NSCLC) treatment because of the increasing number of drugs that target genomic rearrangements. A multiplex test that can detect multiple gene mutations prior to treatment is thus necessary. Currently, either next-generation sequencing (NGS)-based or polymerase chain reaction (PCR)-based tests are used. We evaluated the performance of the Oncomine Dx Target Test (ODxTT), an NGS-based multiplex biomarker panel test, and the AmoyDx Pan Lung Cancer PCR Panel (AmoyDx PLC panel), a real-time PCR-based multiplex biomarker panel test. Patients with histologically diagnosed NSCLC and a sufficient sample volume to simultaneously perform the AmoyDx PLC panel and ODxTT-M were included in the study. The success and detection rates of both tests were evaluated. Biopsies revealed 116 cases of malignancies, 100 of which were NSCLC. Of these, 59 met the inclusion criteria and were eligible for analysis. The success rates were 100% and 98% for AmoyDx PLC panel and ODxTT-M, respectively. Nine driver mutations were detected in 35.9% and 37.3% of AmoyDx PLC and ODxTT-M panels, respectively. EGFR mutations were detected in 14% and 12% of samples using the AmoyDx PLC panel and ODxTT-M, respectively. Of the 58 cases in which both NGS and AmoyDx PLC panels were successful, discordant results were observed in seven cases. These differences were mainly due to different sensitivities of the detection methods used and the gene variants targeted in each test. The AmoyDx PLC panel, a PCR-based multiplex diagnostic test, exhibits a high success rate. The frequency of the nine genes targeted for treatment detected by the AmoyDx PLC panel was comparable to the frequency of mutations detected by ODxTT-M. Clinicians should understand and use the AmoyDx PLC panel and ODxTT-M with respect to their respective performances and limitations.

Clinicopathological analysis of thyroid carcinomas with the RET and NTRK fusion genes: characterization for genetic analysis

Thyroid carcinomas exhibit various genetic alterations, including the RET and NTRK fusion genes that are targets for molecular therapies. Thus, detecting fusion genes is crucial for devising effective treatment plans. This study characterized the pathological findings associated with these genes to identify the specimens suitable for genetic analysis. Thyroid carcinoma cases positive for the fusion genes were analyzed using the Oncomine Dx Target Test. Clinicopathological data were collected and assessed. Among the 74 patients tested, 8 had RET and 1 had NTRK3 fusion gene. Specifically, of the RET fusion gene cases, 6 exhibited “BRAF-like” atypia and 2 showed “RAS-like” atypia, while the single case with an NTRK3 fusion gene presented “RAS-like” atypia. Apart from one poorly differentiated thyroid carcinoma, most cases involved papillary thyroid carcinomas (PTCs). Primary tumors showed varied structural patterns and exhibited a high proportion of non-papillary structures. Dysmorphic clear cells were frequently observed. BRAF V600E immunoreactivity was negative in all cases. Interestingly, some cases exhibited similarities to diffuse sclerosing variant of PTC characteristics. While calcification in lymph node metastases was mild, primary tumors typically required hydrochloric acid-based decalcification for tissue preparation. This study highlights the benefits of combining morphological and immunohistochemical analyses for gene detection and posits that lymph node metastases are more suitable for genetic analysis owing to their mild calcification. Our results emphasize the importance of accurate sample processing in diagnosing and treating thyroid carcinomas.

Clinical utility of the Oncomine Dx Target Test multi-CDx system and the possibility of utilizing those original sequence data.

Companion diagnostic tests play a crucial role in guiding treatment decisions for patients with non-small cell lung cancer (NSCLC). The Oncomine Dx Target Test (ODxTT) Multi-CDx System has emerged as a prominent companion diagnostic method. However, its efficacy in detecting driver gene mutations, particularly rare mutations, warrants investigation. This study aimed to assess the performance of the ODxTT in detecting driver gene mutations in NSCLC patients. Specifically, we aimed to evaluate its sensitivity in detecting epidermal growth factor receptor (EGFR) mutations, a key determinant of treatment selection in NSCLC. We conducted a retrospective analysis of NSCLC patients who underwent testing with the ODxTT at Keio University Hospital between May 2020 and March 2022. Patient samples were subjected to both DNA and RNA tests. Driver gene mutation status was assessed, and instances of missed mutations were meticulously examined. Of the 90 patients, five had nucleic acid quality problems, while 85 underwent both DNA and RNA tests. Driver gene mutations were detected in 56/90 (62.2%) patients. Of the 34 patient specimens, driver mutations were not detected using the ODxTT; however, epidermal growth factor receptor (EGFR) mutations were detected using polymerase chain reaction-based testing in two patients, and a KRAS mutation was detected by careful examination of the sequence data obtained using the ODxTT in one patient. For the above three cases, carefully examining the gene sequence information obtained using the ODxTT could identify driver mutations that were not mentioned in the returned test results. Additionally, we confirmed comparable instances of overlook results for EGFR mutations in the dataset from South Korea, implying that this type of oversight could occur in other countries using the ODxTT. EGFR mutation was missed in ODxTT in Japan (6.3%, 2/32), South Korea (2.0%, 1/49), and overall (3.7%, 3/81). Even if sufficient tumor samples are obtained, rare EGFR mutations (which are excluded from the ODxTT's genetic mutation list) might not be detected using the current ODxTT system due to the program used for sequence analysis. However, such rare EGFR mutations can still be accurately detected on ODxTT's sequence data using next-generation sequencing.

Simulation analysis of EGFR mutation detection: Oncomine Dx target test and AmoyDx panel impact on lung cancer treatment decisions

Lung cancer is a leading cause of cancer-related deaths worldwide. Epidermal growth factor receptor (EGFR) driver mutations are crucial for treatment decisions for patients with non-small cell lung cancer (NSCLC). This study aimed to assess the differences in EGFR mutation detection between two companion diagnostic (CDx) tests—the Oncomine Dx Target Test (ODxTT) and the AmoyDx Pan Lung Cancer PCR Panel—and their impact on treatment applicability. To this end, we used an in-house targeted sequencing dataset of 282 samples from 127 EGFR-mutated NSCLC patients to simulate the concordance between the EGFR variants targeted by the ODxTT and AmoyDx panel, the oncogenicity of the variants, and their therapeutic potential. Of the 216 EGFR mutations identified by the in-house panel, 51% were detectable by both CDx tests, 3% were specific to ODxTT, and 46% were not targeted by either test. Most non-targeted mutations did not have oncogenicity and were located outside exons 18–21. Notably, 95% of the mutations detectable by both tests had potential oncogenicity. Furthermore, among the 96 patients harboring actionable EGFR mutations, 97% had mutations detectable by both CDx tests and 1% by ODxTT, while 2% had mutations not covered by either test. These findings suggest that while both CDx tests are effective in detecting almost all actionable EGFR mutations, ODxTT provides slightly broader coverage. These results emphasize the importance of selecting appropriate CDx tests to inform treatment decisions for EGFR-positive NSCLC patients.

Impact of the quality of resected thyroid cancer tissue sample on next-generation sequencing testing.

Activating rearranged during transfection (RET) proto-oncogene alterations can be identified using next-generation sequencing (NGS) of tumor DNA/RNA. We assessed factors associated with NGS (Oncomine Dx Target Test [ODxTT]) success for resected thyroid cancer (TC) specimens, including sample age, processing conditions, and DNA/RNA quality. TC samples were from three Japanese hospitals, with sample age <1-<10 years, fixative 10%/15% neutralized buffered formalin (NBF), and fixation time ≤48 h/>48 h-≤72 h. NGS success rate was defined as the percentage of samples returning validated NGS results (RET fusion-positive/negative [RNA] or RET mutation-positive/negative [DNA], detected using ODxTT). DNA/RNA quality was assessed with indexes based on electrophoresis (DNA/RNA integrity number, DV200 ) and quantitative polymerase chain reaction (DNA/RNA integrity score [ddCq/ΔCq]). NGS success rate (N = 202) was 90%/93% (DNA/RNA) overall, 98%-100% (DNA and RNA) for samples <3 years old, and 91% (DNA and RNA) for samples ≥3-<5 years old fixed in 10% NBF for ≤48 h. Multivariate logistic regression analysis identified ddCq and ΔCq as significant predictors of DNA and RNA NGS success rates, respectively. Quality assessment of nucleic acid extracted from archival tissue samples is important for achieving high NGS success rates in clinical practice, especially for samples ≥3 years old.

Cost-effectiveness Analysis of the Oncomine™ Dx Target Test MultiCDx System Using Next-generation Sequencing and Single-gene Test in Advanced and Recurrent Nonsquamous Non-small-cell Lung Cancer.

To determine the appropriate treatment for patients with advanced/recurrent nonsquamous non‒small-cell lung cancer (NSCLC), a companion diagnostic was conducted to detect driver mutations through genetic testing. In Japan, Oncomine Dx Target Test (DxTT) using next-generation sequencing (NGS) that can comprehensively detect gene mutations or single-gene tests are conducted as companion diagnostics. Furthermore, cost-effectiveness analysis was conducted to compare the cost-effectiveness of Oncomine DxTT using NGS with that of single-gene test in Japan. The target population included patients with advanced/recurrent nonsquamous NSCLC. A model structure was constructed for the Oncomine DxTT strategy and three single-gene tests (i.e., epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK)/c-ros oncogene 1 (ROS1) rearrangements) with reference to previous studies and the Clinical Practice Guidelines of Lung Cancer 2022 in Japan. The model structure assumed that genetic testing would be conducted and first-line treatment used the drug most recommended in the 2022 Japanese Lung Cancer Clinical Practice Guidelines, depending on the driver mutation,. Model inputs were obtained from the literature and price list in Japan, and cost-utility analysis was conducted. For the Oncomine DxTT strategy, the expected incremental costs and effectiveness were estimated to be approximately JPY 172,361 (JPY 12,285,228 vs. JPY 12,112,867 for strategies A and B, respectively) and -0.51 quality-adjusted life-year (QALY) per patient (21.93 QALY vs. 22.44 QALY for strategies A and B). As a result, the costs increased but the effectiveness decreased. Therefore, the Oncomine DxTT strategy was dominated by the three single-gene tests. Sensitivity and scenario analyses revealed that the test success rate of Oncomine DxTT affected the results. The genetic test using Oncomine DxTT before the first-line treatment is not cost-effective compared with the three single-gene tests (EGFR/ALK/ROS1) for patients with advanced/recurrent nonsquamous NSCLC.

Influence of formalin fixation duration on RNA quality and quantity from formalin-fixed paraffin-embedded hepatocellular carcinoma tissues.

Analyzing RNA samples from formalin-fixed paraffin-embedded (FFPE) tissues is essential for precision medicine. We investigated RNA quantity and quality from FFPE tumor tissues fixed in formalin for various times and compared sequencing metrics from next-generation sequencing (NGS). Hepatocellular carcinoma (HCC) tissues were fixed in 10% neutral buffered formalin (1-240 h) and FFPE blocks were prepared. Total RNA was extracted, and the quantity and quality were assessed using the NanoDrop, Qubit and Bioanalyzer. After preparing sequencing libraries, NGS was performed on the Oncomine Dx Multi-CDx system. Total RNA yields of all samples met the threshold required for NGS, but longer fixation times resulted in decreased total RNA and long RNA fragment (>200 nt) yields. NGS analysis showed fewer sequencing reads of internal control genes from RNA with longer fixation times. RNA extracted from FFPE blocks stored for 500 days had reduced RNA yield and quality compared with RNA obtained from FFPE blocks prepared immediately. In conclusion, short and over-fixation should be avoided because of their negative impact on sequencing quality. Fixation process should be finished promptly within recommended guidelines (6-72 h) for cancer patients.

Enhancing tumour content and tumour cell count using microdissection contributes to higher detection rate of genetic mutations by next-generation sequencers

BackgroundNext-generation sequencing (NGS) analysis is becoming indispensable for the treatment of advanced lung cancer. NGS analysis requires a large number of cancer cell-containing tissues; however, it is often difficult for small biopsies to obtain the required quantities. In microdissection, only the tumour parts of a tissue specimen are obtained, which thereby increases the tumour content and tumour cell count of the tissue specimen. In this study, we investigated the extent to which the detection rate of genetic mutations changes by increasing the tumour content using microdissection. Patients and methodsThis is a retrospective study. In the genetic panel test using the Oncomine Dx Target Test (ODxTT), participants were divided into two groups: before (group A; April 2021–March 2022) and after (group B; April 2022–December 2022) the introduction of microdissection. The submission criteria for ODxTT were tumour content and tumour cell count >30 % and >2000 in group A, and >40 % and >5000 in group B, respectively. We compared the rate of genetic mutations detected using ODxTT between the two groups. ResultsThis study included 214 consecutive ODxTT cases between April 2021 and December 2022. In group A (n = 112), 65 cases were adenocarcinoma, 84 involved lung tissue, and 64 underwent bronchoscopic sampling, whereas in group B (n = 102), 55 cases were adenocarcinoma, 91 cases involved lung tissue, and 79 cases underwent bronchoscopic sampling. Furthermore, genetic mutations were detected in 39 of 112 cases (35 %) in group A and 59 of 102 cases (58 %) in group B, which was statistically higher in group B (P = 0.0006). Genetic mutations were detected in 45 of 55 adenocarcinoma cases in group B. The genetic mutations detected in epidermal growth factor rescepor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS), and mesenchymal epithelial transition (MET) were higher in group B. ConclusionIncreasing the number of tumour cells and tumour content can enhance the detection rate of genetic mutations using ODxTT.

554P Comparison of the analytical performance of endobronchial ultrasound-guided transbronchial needle aspiration and other sampling methods for the Oncomine Dx target test: An observational study

554P Comparison of the analytical performance of endobronchial ultrasound-guided transbronchial needle aspiration and other sampling methods for the Oncomine Dx target test: An observational study

THU510 The Frequency Of Mutations In Advanced Thyroid Cancer In Japan: A Real Clinical Setting

Abstract Disclosure: S. Toda: None. A. Takahashi: None. K. Masudo: None. H. Iwasaki: None. Background: Thyroid cancer has a high incidence of actionable genetic alterations, but the frequency of mutations in advanced thyroid cancer that requires drug therapy is unknown. Therefore, we examined the outcomes of genetic testing performed in a real clinical setting for the purpose of pharmacotherapy. Methods: In Japan, Oncomine Dx is approved for thyroid cancer that requires drug therapy, and comprehensive genomic profiling is approved for anaplastic thyroid carcinoma and other thyroid carcinomas after the induction of tyrosine kinase inhibitors. We retrospectively reviewed the cases of those who had their tests performed between 2020 and 2022. Results: The study included 65 patients, and the testing methods used were Oncomine Dx in 36 cases, FoundationOne in 25 cases, and FoundationOne Liquid in 4 cases. With a median age of 74 years (range 17–86), 42 were female and 23 were male. Moreover, 13 cases had anaplastic thyroid carcinoma (ATC), 4 follicular thyroid carcinoma (FTC), 42 papillary thyroid carcinoma (PTC), and 6 poorly differentiated thyroid carcinoma (PDTC). Of the PTC examined by Oncomine Dx, 96.8% (30/31) were RAI-refractory; all comprehensive genomic profiling testing cases except ATC had previously been treated with tyrosine kinase inhibitors. In the following cases, actionable mutations were observed. Among 13 ATC cases, 46.2% (6) had BRAF mutation and 7.7% (1) had RET fusion. Of 42 PTC cases, 85.7% (36) had BRAF mutation and 7.1% (3) had RET fusion. Of 6 PDTC cases, 33.3% (2) had BRAF mutation and 16.7% (1) had RET fusion. No actionable mutations were observed in FTC (0/4). We found one case each of ATC and PTC with tumor mutation burden of 10 or higher, both with BRAF mutation. NTRK fusion was not observed in any of the 65 patients studied. There were four PTC cases (9.5%) with iodine accumulation in metastases, two with BRAF mutations, one with RET fusion, and one without detectable mutations. Comparing mutations in ATC and non-ATC, TERT promoter mutations were found in 84.6% of ATC (11/13) vs. 56.2% of non-ATC (9/16), whereas TP53 mutations were found in 76.9% of ATC (10/13) vs. 12.5% of non-ATC (2/16). ATC has a significantly higher prevalence of TP53 mutations. Conclusion: Advanced thyroid cancer is more likely to have actionable mutations. BRAF mutations in advanced PTC may be more common than those previously reported in standard PTC. Moreover, ATC has a higher rate of TP53 mutation than other thyroid carcinomas. Presentation: Thursday, June 15, 2023

Comparison of the slow-pull and aspiration methods of endobronchial ultrasound-guided transbronchial needle aspiration for next-generation sequencing-compatible tissue collection in non-small cell lung cancer.

Personalized treatment for non-small cell lung cancer (NSCLC) has advanced rapidly, and elucidating the genetic changes that trigger this disease is crucial for appropriate treatment selection. Both slow-pull and aspiration methods of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) are accepted methods for collecting samples suitable for next-generation sequencing (NGS) to examine driver gene mutations and translocations in NSCLC. Here, we aimed to determine which of these two methods is superior for obtaining higher-quality samples from patients with NSCLC. Seventy-one patients diagnosed with NSCLC via EBUS-TBNA using the slow-pull or aspiration (20-mL negative pressure) methods between July 2019 and September 2022 were included. A total of 203 tissue samples from the 71 patients were fixed in formalin, embedded in paraffin, and mounted on slides. The presence of tissue cores, degree of blood contamination, and number of tumor cells were compared between the groups. The success rate of NGS, using Oncomine Dx Target Test Multi-CDx, was also compared between the groups. The slow-pull method was associated with a higher yield of tissue cores, lower degree of blood contamination, and higher number of tumor cells than the aspiration method. The success rate of the NGS was also significantly higher for the slow-pull group (95%) than for the aspiration group (68%). Overall, these findings suggest that the slow-pull method is a superior technique for EBUS-TBNA to obtain high-quality tissue samples for NGS. The slow-pull method may contribute to the identification of driver gene mutations and translocations and facilitate personalized treatment of NSCLC.

Clinical importance of the range of detectable variants between the Oncomine Dx target test and a conventional single-gene test for EGFR mutation

Although we have experienced some cases with discordant results between the Oncomine Dx target test (ODxTT) and conventional single gene tests for detecting EGFR alterations, the clinical efficacy of EGFR-TKIs in these discordant cases remains little known. We retrospectively reviewed consecutive patients with non-small-cell lung cancer whose FFPE samples were simultaneously submitted for the ODxTT, and a PNA-LNA PCR clamp test. We evaluated the clinical efficacy of EGFR-TKIs in patients with discordant results between the two tests, focusing on the common EGFR mutations. Among 444 successful results, 10 patients had discordant results for common EGFR mutations (9 Ex 19 deletion and 1 Ex 21 L858R mutation), and all of these were detected only by the PNA-LNA PCR clamp test. Among six discordant cases treated with EGFR-TKI, the mutations detected in 3 patients were not included in the list of detectable variants that are reportable by the ODxTT, while the mutations detected in the other 3 patients were included in the list. For all three discordant cases harboring the mutations not reportable by the ODxTT, good clinical responses were demonstrated. However, among the other three discordant cases harboring the mutations reportable by the ODxTT, only one patient had a clinical response with short duration. Among the discordant cases for common EGFR mutations between the ODxTT and the conventional single gene test, there are a certain number of suitable patients responsive to EGFR-TKIs, especially when the cause of the discordant results comes from the difference in the range of detectable variants that are reportable between the tests.