High Yield of RNA Sequencing for Targetable Kinase Fusions in Lung Adenocarcinomas with No Mitogenic Driver Alteration Detected by DNA Sequencing and Low Tumor Mutation Burden

The fusion characteristics of RET fusion in pan-cancer among the Chinese population: A comprehensive genomic analysis

BACKGROUND

RET fusions are significant oncogenic drivers, resulting from chromosomal rearrangements of the RET proto-oncogene with various partner genes. Understanding their structural characteristics is crucial for elucidating oncogenic potential and developing targeted therapies.

METHODS

This study analyzed 21,023 tumor samples and 3716 peripheral blood samples from a Chinese pan-cancer cohort using DNA or RNA-targeted next-generation sequencing (NGS). 19,668 tissues underwent DNA-based fusion detection and 1355 NSCLC tissues underwent RNA-based fusion detection using a 733-gene panel. ctDNA-based targeted NGS was also performed on blood samples.

RESULTS

RET fusions were detected in 1.027 % of tissue samples, predominantly lung and thyroid cancers. Compared to Western populations (87 % in intron 11), Chinese patients show a shift toward the exon 10-11 region, with 30.79 % in intron 10. RET rearrangements were classified into four categories (Simple Reciprocal Inversion, Co-Fusion, Single Fusion-Common, Single Fusion-Rare) with unique mutational profiles and tumor mutational burden scores. RNA-based NGS revealed some DNA-detected rearrangements might not undergo transcription, while Co-Fusion indicated potential simultaneous transcription of multiple RET fusions. An NSCLC patient with KIF5B-RET and ATRNL1-RET co-fusions achieved 15-month progression-free survival on RET-targeted therapy.

CONCLUSION

This study underscores the importance of structural insights for developing targeted therapies against RET fusion-driven cancers and highlights the need for further investigation into complex RET fusion mechanisms to better understand RET-driven oncogenesis.

Emerging importance of HER3 in tumorigenesis and cancer therapy

HER3 is a member of the HER/ErbB family of receptor tyrosine kinases, together with EGFR (HER1), HER2 and HER4. Despite having only weak intrinsic kinase activity, HER3 can contribute to oncogenic signalling via ligand-induced heterodimerization with other HER family members. Evidence indicates that HER3 is altered or aberrantly expressed across a variety of tumour types and can be associated with poor clinical outcomes. Whereas anticancer agents targeting EGFR and HER2 have been approved for decades, no drug targeting HER3 had been approved until very recently. Initial targeting of HER3 with monoclonal antibodies as single agents or in combination with other therapeutics produced disappointing clinical results. Subsequently, efforts have been made to target HER3 with novel agents such as antibody-drug conjugates and bispecific antibodies, with promising efficacy observed in several trials encompassing various tumour types. In December 2024, the HER3 × HER2 bispecific antibody zenocutuzumab was granted FDA Accelerated Approval for the treatment of non-small-cell lung cancers or pancreatic cancers harbouring fusions involving NRG1, the gene encoding the high-affinity HER3 ligand neuregulin 1. In this Review, we provide an essential guide to HER3 signalling and oncogenesis, HER3 expression in cancer and its prognostic implications, oncogenic HER3 somatic mutations as well as rare NRG1 fusions that might depend on HER3 signalling, and the roles of HER3 in resistance to cancer therapies. We also highlight efforts to target HER3 with diverse therapeutic strategies and the potential interplay between HER3 and the antitumour immune response.

Oncogenic gene fusions in cancer: from biology to therapy

Oncogenic gene fusions occur across a broad range of cancers and are a defining feature of some cancer types. Cancers driven by gene fusion products tend to respond well to targeted therapies, where available; thus, detection of potentially targetable oncogenic fusions is necessary to select optimal treatment. Detection methods include non-sequencing methods, such as fluorescence in situ hybridization and immunohistochemistry, and sequencing methods, such as DNA- and RNA-based next-generation sequencing (NGS). While NGS is an efficient way to analyze multiple genes of interest at once, economic and technical factors may preclude its use in routine care globally, despite several guideline recommendations. The aim of this review is to present a summary of oncogenic gene fusions, with a focus on fusions that affect tyrosine kinase signaling, and to highlight the importance of testing for oncogenic fusions. We present an overview of the identification of oncogenic gene fusions and therapies approved for the treatment of cancers harboring gene fusions, and summarize data regarding treating fusion-positive cancers with no current targeted therapies and clinical studies of fusion-positive cancers. Although treatment options may be limited for patients with rare alterations, healthcare professionals should identify patients most likely to benefit from oncogenic gene fusion testing and initiate the appropriate targeted therapy to achieve optimal treatment outcomes.

eNRGy: Making progress toward a future for NRG1 fusion-positive cancer

The eNRGy trial demonstrated zenocutuzumab's efficacy in advanced cancer with NRG1 fusion, mainly non-small cell lung and pancreatic cancers.1 Responses were observed across multiple tumor types identified through RNA-based next-generation sequencing, with low-grade adverse events. This suggests a potentially agnostic role of NRG1 fusions in solid tumors and underscores the need for comprehensive gene fusion testing in patients with cancer.

Integrating comprehensive genomic profiling in the management of oncology patients: applications and challenges in Taiwan

Comprehensive genomic profiling (CGP) refers to the detailed genomic analysis of cancers for oncology patients. With the rapid development of next-generation sequencing (NGS) technologies, CGP has been widely applied to clinical practice and managing oncology patients. CGP can be performed on the tumor DNA and RNA, as well as non-tumor tissues (e.g., blood, pleural effusion, and ascites). In this article, we review the current evidence supporting the use of CGP in the management of oncology patients, both in real-world practice and the bridging to clinical trials. We also discuss the role of the molecular tumor board on the application of CGP in oncology patients. We provide an overview of the current scheme of CGP reimbursement in Taiwan and the precision oncology branch of the National Biobank Consortium of Taiwan. Finally, we discuss about the potential barriers and challenges of applying CGP in managing oncology patients and the future perspectives of CGP in precision oncology.

Targeted RNA sequencing in diagnostically challenging head and neck carcinomas identifies novel MON2::STAT6, NFATC2::NUTM2B, POC5::RAF1, and NSD3::NCOA2 gene fusions

AIMS

Although molecular tests developed for a growing list of oncogenic alterations have significantly aided in the classification of head and neck carcinomas, tumours in which prototypical histologic and immunophenotypic features are lacking or only partially developed continue to pose diagnostic challenges. Searching for known diagnostic and therapeutic targets by clinical next-generation sequencing (NGS) assays can often lead to new discoveries.

METHODS AND RESULTS

We present our institutional experience in applying targeted RNA NGS in 36 head and neck carcinomas that were morphologically difficult to classify between 2016 and 2023. The patients ranged in age from 5 to 83 years (median, 64), with the majority of tumors occurring in the major salivary glands and the sinonasal tract. Overall, seven (19%) cases showed unusual gene rearrangements, including five novel alterations: MON2::STAT6 in a hard palate adenocarcinoma with mucinous features, POC5::RAF1 in apocrine intraductal carcinoma of the lacrimal gland, EWSR1::CDADC1 fusion in a basaloid carcinoma of the submandibular gland, NFATC2::NUTM2B in myoepithelial carcinoma, and NSD3::NCOA2 fusion in a peculiar high-grade carcinoma with a peritheliomatous growth pattern, and focal myogenic differentiation. Potential therapeutic actionability was identified in three cases (RAF1 and FGFR2 fusions).

CONCLUSION

These findings broaden the current spectrum of gene rearrangements in head and neck carcinomas and support the utility of clinical NGS in identifying unusual, actionable alterations in diagnostically challenging cases.

Prognostic potential of fusion gene analysis using plasma cell-free RNA in malignant bone and soft tissue tumours

BACKGROUND

Liquid biopsy, which facilitates minimally invasive analysis of body fluid samples, has considerable potential as a diagnostic and prognostic tool in various cancers. Analysis of circulating tumour cells, circulating tumour DNA, and exosomes in liquid biopsies has advantages and disadvantages. However, their utility in rare cancers, such as malignant bone and soft tissue tumours, remains unknown. In this study, we examined the levels of circulating cell-free tumour RNA (cfRNA) in the blood of patients with malignant bone and soft tissue tumours harbouring specific fusion genes, to explore the relationship between fusion gene expression in the blood and therapeutic response and disease status, and to validate the clinical utility of liquid biopsy.

METHODS

The study involved 3 cases (7 samples) of Ewing's sarcoma, 6 cases (12 samples) of myxoid liposarcoma, and 1 case (2 samples) of synovial sarcoma with specific fusion genes. Fusion gene analysis was performed using tumour tissue samples to identify breakpoints. Primers for liquid biopsy were designed based on the fusion genes identified. cfRNA was extracted from each patient's plasma and used for reverse transcription polymerase chain reaction (RT-PCR) with the designed primers. The RT-PCR product was subjected to Sanger sequencing.

RESULTS

Fusion gene breakpoints were identified in 10 samples from 6 cases. The fusion gene detection rate in the blood was 100% at both naïve status and symptom exacerbation in patients with Stage IV disease. In patients with Stage III disease progressing to Stage IV, the fusion gene was detected in the blood prior to imaging tests.

CONCLUSIONS

The detection of specific fusion genes from cfRNAs shows potential for monitoring the progression of fusion-related sarcomas in the context of chemotherapy.

Prognostic and predictive biomarkers with therapeutic targets in nonsmall-cell lung cancer: A 2023 update on current development, evidence, and recommendation

BackgroundSince the publication of the original work in 2014, significant progress has been made in the characterization of genomic alterations that drive oncogenic addiction of nonsmall cell lung cancer (NSCLC) and how the immune system can leverage non-oncogenic pathways to modulate therapeutic outcomes. This update evaluates and validates the recent and emerging data for prognostic and predictive biomarkers with therapeutic targets in NSCLC.Data sourcesWe performed a literature search from January 2015 to October 2023 using the keywords non-small cell lung cancer, clinical practice guidelines, gene mutations, genomic assay, immune cancer therapy, circulating tumor DNA, predictive and prognostic biomarkers, and targeted therapies.Study selection and data extractionWe identified, reviewed, and evaluated relevant clinical trials, meta-analyses, seminal articles, and published clinical practice guidelines in the English language.Data synthesisRegulatory-approved targeted therapies include those somatic gene alterations of EGFR ("classic" mutations, exon 20 insertion, and rare EGFR mutations), ALK, ROS1, BRAF V600, RET, MET, NTRK, HER2, and KRAS G12C. Data for immunotherapy and circulating tumor DNA in next-generation sequencing are considered emerging, whereas the predictive role for PIK3CA gene mutation is insufficient.ConclusionsAdvances in sequencing and other genomic technologies have led to identifying novel oncogenic drivers, novel resistance mechanisms, and co-occurring mutations that characterize NSCLC, creating further therapeutic opportunities. The benefits associated with immunotherapy in the perioperative setting hold initial promise, with their long-term results awaiting.

Lung Carcinoid Tumors With Potentially Actionable Genomic Alterations and Responses to Targeted Therapies

BACKGROUND

Effective treatments for patients with advanced lung carcinoids remain limited. The prevalence of potentially actionable genomic alterations (AGAs) among lung carcinoids is not well-understood.

MATERIALS AND METHODS

Lung carcinoids submitted for next-generation sequencing (NGS) at a Clinical Laboratory Improvement Amendments (CLIA)-certified genomics laboratory from September 2013 to March 2024 were retrospectively investigated to determine prevalence of AGAs. We evaluated outcomes with genotype-matched targeted therapies in patients with advanced lung carcinoids with AGAs identified across 3 institutions and comprehensive literature search.

RESULTS

Among 321 cases of lung carcinoids profiled by NGS, 8 (2.5%) harbored potential AGAs (4 [1.2%] with commercially available targeted therapies), including KRAS mutations (n = 4, 1.2%: G12C, G12D, G12R, G12V), ALK fusions (n = 2, 0.6%), BRAF D594N (n = 1, 0.3%), and RET fusion (n = 1, 0.3%). None of the 24 typical carcinoids harbored an AGA. Collectively across these database-identified patients, our multi-institutional cohort, and literature review, we identified 36 cases of lung carcinoids with potential AGAs (24 with commercially available targeted therapies), predominantly comprising fusions of ALK (n = 14), RET (n = 5), and NTRK (n = 2). Of 27 with known disease stage, 19 had stage 4 disease, and 13 (68.4%) had outcomes reported following targeted therapies. Median treatment duration was 12.0 months (95% CI: 6.7-16.0). Median progression-free survival (PFS) was 10.6 months (95% CI: 6.7-16.0) across all targeted therapy lines and 14.0 months (95% CI: 1.3-NA) with first-line targeted therapies. Objective response rate with at least one targeted therapy was 61.5%.

CONCLUSIONS

Patients with advanced lung carcinoids harboring AGAs can derive meaningful benefit from genotype-matched targeted therapies, highlighting potential role for NGS in patients with advanced carcinoids.

Comparison of Targeted RNA-Sequencing Platforms for Oncogenic Fusion Detection in Non-Small-Cell Lung Cancer

Oncogenic fusion detection is an essential part of clinical diagnosis and management of non-small-cell lung carcinoma. Numerous methods are available for detection of oncogenic fusions in the clinical laboratory, although RNA sequencing has rapidly gained prominence. Accordingly, however, multiple different RNA-sequencing assays exist, with diverse methods and varying performance characteristics. Here, a single-institutional clinical experience with a testing algorithm for non-small-cell lung carcinoma that uses amplicon-based DNA/RNA sequencing, followed by reflex hybridization-capture-based RNA sequencing if the initial testing is negative for oncogenic drivers, is reported. A total of 1211 non-small-cell lung carcinoma specimens were received for molecular testing, and 120 (approximately 10%) were reflexed for hybridization-capture-based RNA sequencing. Of the 120 cases tested, oncogenic fusions were identified in 9 and included clinically actionable fusions involving ALK, BRAF, NRG1, NTRK3, ROS1, and RET. None of these fusions was detected by the amplicon-based assay. Review of the 20,900 non-small-cell lung cancer cases in the American Association for Cancer Research Project Genie version 15.1 publicly available database (registration required) revealed that of the 1081 cases harboring fusions, 893 (82.6%) could theoretically be detected by the amplicon-based assay. Overall, this study shows that the addition of reflex hybridization-capture-based RNA sequencing could improve detection of rare and novel oncogenic fusions, maximizing patient eligibility for appropriate targeted therapies or clinical trials.

Emerging molecular testing paradigms in non-small cell lung cancer management-current perspectives and recommendations

Advances in molecular testing and precision oncology have transformed the clinical management of lung cancer, especially non-small cell lung cancer, enhancing diagnosis, treatment, and outcomes. Practical guidelines offer insights into selecting appropriate biomarkers and assays, emphasizing the importance of comprehensive testing. However, real-world data reveal the underutilization of biomarker testing and consequently targeted therapies. Molecular testing often occurs late in diagnosis or not at all in clinical practice, leading to delayed or inadequate treatment. Enhancing precision requires adherence to best practices by all health care professionals involved, which can ultimately improve lung cancer patient outcomes. The future of precision oncology for lung cancer will likely involve a more personalized approach, starting increasingly from earlier disease settings, with novel and more complex targeted therapies, immunotherapies, and combination regimens, and relying on liquid biopsies, muti-detection advanced genomic technologies and data integration, with artificial intelligence as a central orchestrator. This review presents the currently known actionable mutations in lung cancer and new upcoming ones that are likely to enter clinical practice soon and provides an overview of established and emerging concepts in testing methodologies. Challenges are discussed and best practice recommendations are made that are relevant today, will continue to be relevant in the future, and are likely to be relevant for other cancer types too.

The implementation of an RNA-based gene fusion assay into a diagnostic oncology department: an Australian perspective

Accurate detection of oncogenic gene fusions is important for histological diagnosis of a subset of tumours. Some fusions are also the target of precision therapies. We describe our validation and early diagnostic results for the detection of fusions using the commercially available Illumina TruSight RNA Fusion Panel (TRFP) and the Arriba fusion detection algorithm. Retrospective validation showed that this assay demonstrated high accuracy (94% positive predictive agreement) for a wide variety of fusions. Prospective diagnostic data comprised a cohort of 131 clinical samples (102 mesenchymal tumours, 29 epithelial tumours), of which 80 were excisional specimens and 51 were small specimens, predominantly core biopsies. The test failure rate was 10.7%. We detected 64 (54.7%) clinically-actionable fusions in passed samples, including 12 (10.3%) that either changed or were critical for the diagnosis and 14 (12.0%) that were potentially therapeutically targetable. Most samples (89.7%) fulfilled criteria for partial reimbursement by the Australian Government Medical Benefits Scheme. In addition to describing the utility of an RNA-based fusion assay in cancer diagnostics, it is hoped that this study will provide practical advice for other laboratories considering introducing such a test.

[Molecular characterization of lung cancers: up-date and recommendations]

Molecular testing of non-small cell lung cancers has become mandatory at all stages of the disease. National and international recommendations for molecular testing are up-dated regularly. In this review, we will summarize diagnostic approaches focusing on targetable oncogenic alterations (mutations, gene rearrangements) and we will indicate the limits currently associated with sample types and sequencing technologies. Biomarkers that have not showed routine clinical utility will not be presented here.

An accurate DNA and RNA based targeted sequencing assay for clinical detection of gene fusions in solid tumors

Gene fusions are one of the most important molecular biomarkers for tumor diagnosis, classification and targeted therapy. How to accurately detect them is a key issue in clinical work. In this study, a custom-designed integration of DNA and RNA-based next generation sequencing (NGS) assay including 16 targeted therapy related genes was developed and validated to identify gene fusions in solid tumors. This assay accurately identified all 10 different types of fusion in 8 commercial fusion spiked-in reference standards and 29 fusions including 16 different fusion forms in 60 clinical solid tumor samples previously identified by clinical testing methods. In addition, a TPM3::NTRK1 fusion was additionally identified and validated by Sanger sequencing, which showed a false-negative result for the previous result. Mutational abundance limit of detection for the assay was assessed with a series of dilution experiments. These fusions can be stably detected when the mutational abundance is down to 5% for DNA and 250-400 copies/100 ng for RNA. The intra-assay and inter-assay reproducibility was observed in three samples and three replicates. This integration of DNA and RNA-based NGS assay shows excellent performance on formalin-fixed, paraffin-embedded samples, results at different levels can complement each other, thereby facilitating precise diagnosis and treatment.

Efficacy of Zenocutuzumab in NRG1 Fusion-Positive Cancer

BACKGROUND

Neuregulin 1 (NRG1) fusions are recurrent oncogenic drivers found in multiple solid tumors. NRG1 binds to human epidermal growth factor receptor 3 (HER3), leading to heterodimerization with HER2 and activation of downstream growth and proliferation pathways. The efficacy and safety of zenocutuzumab, a bispecific antibody against HER2 and HER3, in patients with NRG1 fusion-positive solid tumors are unclear.

METHODS

In this registrational, phase 2 clinical study, we assigned patients with advanced NRG1 fusion-positive cancer involving any tumor type to receive zenocutuzumab at a dose of 750 mg intravenously every 2 weeks. The primary end point was overall response (complete or partial response) according to investigator assessment. Secondary end points included duration of response, progression-free survival, and safety.

RESULTS

A total of 204 patients with 12 tumor types were enrolled and treated. Among 158 patients who had measurable disease and were enrolled at least 24 weeks before the data-cutoff date, a response occurred in 30% (95% confidence interval [CI], 23 to 37). The median duration of response was 11.1 months (95% CI, 7.4 to 12.9); 19% of responses were ongoing at the data-cutoff date. Responses were observed in multiple tumor types - including in 27 of 93 patients (29%; 95% CI, 20 to 39) with non-small-cell lung cancer (NSCLC) and 15 of 36 patients (42%; 95% CI, 25 to 59) with pancreatic cancer - and across multiple NRG1 fusion partners. The median progression-free survival was 6.8 months (95% CI, 5.5 to 9.1). Adverse events were primarily grade 1 or 2. The most common adverse events that were considered by the investigator to be related to zenocutuzumab were diarrhea (in 18% of the patients), fatigue (in 12%), and nausea (in 11%). Infusion-related reactions (composite term) were observed in 14% of the patients. One patient discontinued zenocutuzumab owing to a treatment-related adverse event.

CONCLUSIONS

Zenocutuzumab showed efficacy in patients with advanced NRG1 fusion-positive cancer, notably NSCLC and pancreatic cancer, with mainly low-grade adverse events. (Funded by Merus; eNRGy ClinicalTrials.gov number, NCT02912949.).

FGFR2 fusions assessed by NGS, FISH, and immunohistochemistry in intrahepatic cholangiocarcinoma

BACKGROUND

FGFR2 fusion has become a promising therapeutic target in iCCAs; however, the procedure for screening FGFR2 fusion has not been conventionally developed.

METHODS

FGFR2 fusion was identified using DNA + RNA-based NGS and FISH, and the concordance between DNA + RNA-based NGS, FISH, and IHC was compared.

RESULTS

FGFR2 fusions were detected in 9 out of 76 iCCAs (11.8%). The consistency of FISH and DNA + RNA-based NGS for FGFR2 fusions was high (κ value = 0.867, P = 0.001), while the consistency of IHC and DNA + RNA-based NGS was lower (κ value = 0.464, P = 0.072). All nine FGFR2 fusion-positive iCCAs were MSS with a median TMB of 2.1 mut/Mb, and only one had a CPS (PD-L1) above 5. Two FGFR2 fusion-positive iCCA patients were treated with and benefited from FGFR inhibitor therapy.

CONCLUSIONS

FGFR2 fusion should be assessed for advanced iCCA patients. We recommend DNA + RNA-based NGS as the preferred option to supply all possible therapeutic targets. FISH should be preferred if the tumor sample is insufficient for NGS or if the patient is inclined to receive FGFR inhibitors promptly. Although IHC is not the preferred method to identify FGFR2 fusion, it might be used as preliminary screening for FGFR2 alterations if the hospital cannot offer NGS or FISH, and the results need to be validated before FGFR2 inhibitors treatment.

Clinicogenomic landscape of pancreatic adenocarcinoma identifies KRAS mutant dosage as prognostic of overall survival

Nearly all pancreatic adenocarcinomas (PDAC) are genomically characterized by KRAS exon 2 mutations. Most patients with PDAC present with advanced disease and are treated with cytotoxic therapy. Genomic biomarkers prognostic of disease outcomes have been challenging to identify. Herein leveraging a cohort of 2,336 patients spanning all disease stages, we characterize the genomic and clinical correlates of outcomes in PDAC. We show that a genomic subtype of KRAS wild-type tumors is associated with early disease onset, distinct somatic and germline features, and significantly better overall survival. Allelic imbalances at the KRAS locus are widespread. KRAS mutant allele dosage gains, observed in one in five (20%) KRAS-mutated diploid tumors, are correlated with advanced disease and demonstrate prognostic potential across disease stages. With the rapidly expanding landscape of KRAS targeting, our findings have potential implications for clinical practice and for understanding de novo and acquired resistance to RAS therapeutics.

NRG1 Fusions: The New Kid on the Block

PURPOSE OF REVIEW

Neuregulin 1 (NRG1) fusions are rare but actionable oncogenic drivers that occur in a variety of tumor types, including non-small cell lung cancer (NSCLC). These fusions lead to pathophysiologic activation of HER signaling pathways, promoting tumor growth, invasion, and metastasis. Current evidence suggests that NRG1 fusion-positive NSCLC does not respond well to conventional treatments such as immunotherapy and chemotherapy. This review focuses on the biology and detection of NRG1 fusions and the evolving therapeutic landscape of NSCLC harboring NRG1 fusions.

RECENT FINDINGS

Zenocutuzumab, a bispecific antibody targeting HER2 and HER3, is the first FDA approved treatment for previously treated NRG1 fusion-positive NSCLC and pancreatic cancer. Additional NRG1 fusion directed strategies are in development. NRG1 fusions are rare molecular drivers of NSCLC that can be effectively treated with targeted therapies. Here, we summarize the biology and detection of NRG1 fusions, the currently approved bispecific antibody used to treat NRG1 fusion-positive NSCLC, and new agents under investigation.

Comprehensive study of gene fusions in sarcomas

Sarcomas, including bone sarcomas and soft tissue sarcomas (STSs), are a heterogeneous group of mesenchymal malignancies. Recent advancements in next-generation sequencing (NGS) have enabled the identification of novel chromosomal translocations and fusion genes, which play a critical role in sarcoma subtypes. Our study focuses on gene fusions in sarcomas among Chinese patients, comparing their genomic profiles to those of Western populations. We analyzed 1048 sarcoma samples from Chinese patients using a panel of over 500 genes, identifying 481 gene fusions in 329 patients. The most common fusions included EWSR1, HMGA2, and SS18, with notable subtype-specific fusions such as EWSR1-FLI1 in Ewing sarcoma and NAB2-STAT6 in solitary fibrous tumors. In comparison to Chinese and Western populations, variations in fusion spectrum exist, potentially necessitating distinct treatment strategies; however, further validation of these fusions is warranted. Our findings highlight the importance of gene fusions as diagnostic markers and potential therapeutic targets. Actionable fusions, including kinase-related fusions like ALK, NTRK3, and BRAF, were detected in 67 patients (6.4%) and may guide precision therapies. Additionally, we observed the frequent co-occurrence of genomic alterations, particularly in cell cycle regulators such as CDK4 and MDM2. Genomic profiling of sarcomas offers valuable insights into their molecular drivers and can support personalized therapeutic approaches. Further research is needed to validate these findings and optimize treatment strategies for sarcoma patients.

Identification of gastric cancer subtypes based on disulfidptosis-related genes: GPC3 as a novel biomarker for prognosis prediction

Gastric cancer (GC) is the fourth most common cancer type. "Disulfidptosis," a distinct form of cell death, is initiated through aberrant intracellular disulfide metabolism. Here, we identified various GC subtypes based on disulfidptosis-related genes (DRGs) and constructed a risk score model to identify relevant genes to help predict patient prognosis and guide treatment. We downloaded RNA sequencing (RNA-seq) data from the TCGA-STAD database, performed a difference analysis, and combined the data with GSE84437 to successfully perform an unsupervised clustering analysis based on DRGs and differentially expressed genes (DEGs). Risk-scoring models were established by screening prognosis-related DEGs. The GC samples were segregated into high-risk (HR) and low-risk (LR) groups according to their risk scores. We then evaluated the genes screened with the model in terms of prognosis, tumor, and immune cell infiltration. The response of patients with GC to immunological therapy was assessed using tumor mutational burden, microsatellite instability, and tumor immune dysfunction and exclusion scores. Using unsupervised cluster analysis, we identified two DRG clusters and two gene clusters that differed in prognosis and tumor microenvironment. A six-gene model was developed for risk score assessment. The LR group demonstrated superior performance compared to the HR group in terms of immunity, exhibiting greater sensitivity to immunotherapy. Thereafter, we selected the model gene GPC3 for single-gene analysis and verified it by experimental validation. The results demonstrated that GPC3 can serve as a standalone biomarker with promising clinical applicability in the prognostic prediction and clinical management of GC.

Intracranial Response to Selpercatinib After Pralsetinib-Induced Disease Progression in Rearranged During Transfection Fusion-Positive Non-Small-Cell Lung Cancer: Case Report

RET fusion-positive NSCLC accounts for 1% to 2% of lung carcinoma cases. Although two Food and Drug Administration-approved selective RET inhibitors, pralsetinib, and selpercatinib, have revealed efficacy in managing RET fusion-positive NSCLC, this case series is unique in its focus on the intracranial response to selpercatinib after disease progression during pralsetinib treatment. This report contributes to the literature by providing evidence of selpercatinib's potential as a treatment option in such refractory cases. The patients described in both cases were diagnosed with metastatic RET fusion-positive NSCLC and developed intracranial metastases during pralsetinib treatment. After switching to selpercatinib, both exhibited significant intracranial responses. The first patient reported a reduction in brain metastasis size and maintained a response for over 1.5 years. The second patient also responded intracranially to selpercatinib but unfortunately passed away 8 months later owing to pulmonary hemorrhage, possibly linked to prior radiation treatment. These cases highlight the potential efficacy of selpercatinib in treating intracranial metastases in RET fusion-positive patients with NSCLC after pralsetinib-refractory progression. The key takeaway is that selpercatinib may offer a viable treatment option in such scenarios, although more extensive studies are needed to determine its role as a monotherapy or in combination with other treatments.

Discovery of Gene Fusions in Driver-Negative Cancer Samples From the National Cancer Institute-Molecular Analysis for Therapy Choice Screening Cohort

PURPOSE

The National Cancer Institute-Molecular Analysis for Therapy Choice (NCI-MATCH) trial was implemented to identify actionable genetic alterations across cancer types and enroll patients accordingly onto treatment arms, irrespective of tumor histology. Using multiplex polymerase chain reaction (PCR) next-generation sequencing, NCI-MATCH genotyped 5,540 patients, discovering gene fusions in 202/5,540 tumors (3.65%). This result, substantially lower than the fusion detection prevalence of 8.5% across all patients with cancer screened at Massachusetts General Hospital's (MGH) clinical laboratories, supported reanalysis of NCI-MATCH samples identified as mutations-of-interest (MOI)-negative. The assay used by NCI-MATCH requires previous knowledge of both fusion genes, cannot detect novel fusions, and may underestimate fusion-positive patients. Anchored multiplex PCR (AMP) technology permits fusion detection with knowledge of just one gene of the fusion partners.

METHODS

Using AMP-based kits, we reprocessed 663 MOI-negative samples. 200 ng of RNA per sample were shipped from the Eastern Cooperative Oncology Group-American College of Radiology Imaging Network biorepository to MGH (n = 319) and Yale University (n = 344), processed, and sequenced on the NextSeq550. Reported fusions were manually reviewed, and novel fusions orthogonally verified via reverse-transcription PCR and Sanger sequencing.

RESULTS

AMP identified 148 fusions in 142/663 MOI-negative patients (21% [95% CI, 18 to 25]), of which 28 were covered by the Oncomine Comprehensive Assay (OCA) panel but missed, while 120 were not covered by OCA. Among AMP-identified positive patients, 32 had actionable fusions, 24 contained novel fusions, and six had two fusion events. We identified fusions in 12/34 (35% [95% CI, 20 to 54]) cholangiocarcinomas and 43/109 (39% [95% CI, 30 to 49]) sarcomas.

CONCLUSION

Technology and awareness of actionable fusions have improved since the NCI-MATCH trial. With AMP-based technology, we identified 142 patients with fusions not detected during NCI-MATCH screening, many potentially actionable. These striking data underscore the need to optimize the fusion-detection capabilities of genotyping assays used in precision medicine.

Evaluation of the ASPYRE-Lung targeted variant panel: a rapid, low-input solution for non-small cell lung cancer biomarker testing and experience from three independent sites

Background

Many patients with non-small cell lung cancer (NSCLC) lack access to highly effective approved targeted therapeutics due to multiple gaps in biomarker testing. Challenges in comprehensive molecular testing include complexities associated with the need to assess the presence of multiple variants, costs of running multiple sequential assays per sample, high assay quality control (QC) failure rates, clinical need for rapid turn-around time (TAT) to initiate therapy, and insufficient tissue samples. The ASPYRE-Lung NSCLC assay addresses gaps in multiplexed testing by simultaneously analyzing DNA and RNA, detecting 114 actionable genomic variants across 11 genes, consistent with current NSCLC treatment guidelines. This study was to assess the ease of adoption and performance of ASPYRE-Lung in third-party laboratories, comparing concordance across sites and with orthogonal methods.

Methods

ASPYRE-Lung was established at two academic centers with multiple operators per site. Assay concordance was evaluated across three sites using 77 patient samples [61 derived from formalin-fixed paraffin-embedded (FFPE) tissue and 16 from cytology specimens].

Results

Reproducibility for all 77 samples yielded a positive percent agreement (PPA) of 100% and negative percent agreement (NPA) of 99.99%. Concordance with next-generation sequencing (NGS)-based methods across all three sites was high with PPA of 97.2% and NPA of 99.96%.

Conclusions

ASPYRE-Lung assay is a cost-effective, easy to adopt testing method requiring no specialized expertise or complicated bioinformatics, with the potential to inform genomic data on small tissue samples, thus enabling all patients with NSCLC to undergo biomarker testing in a timely manner and benefit from appropriate targeted therapies.

Analysis of cancer multigene panel testing for osteosarcoma in pediatric and adults using the center for cancer genomics and advanced therapeutics database in Japan

BACKGROUND

Osteosarcoma (OS) is the most common primary malignant bone tumor. Despite advances in multimodal chemotherapy, prognosis for metastatic or recurrent OS remains poor. Next-generation sequencing (NGS) can uncover new therapeutic options by identifying potentially targetable alterations. This study analyzed NGS data from the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database in Japan, comparing findings with the Memorial Sloan-Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) data from the United States.

METHODS

We sequenced tumor and/or germline DNA from 223 high-grade OS samples using the FoundationOne® CDx or OncoGuideTM NCC Oncopanel System, and the FoundationOne® Liquid CDx for multigene panel testing (2019-2023). Genomic alterations were interpreted using the Cancer Knowledge Database (CKDB), with potentially actionable genetic events categorized into A-F levels.

RESULTS

Analysis of 223 high-grade OS samples revealed 1684 somatic mutations in 167 genes and 1114 copy number alterations in 89 genes. Potentially actionable alterations were identified in 94 patients (42.2 %) at CKDB Levels A-C. These included 2 cases with NTRK fusions (0.9 %; Level A), one case with TMB-high (0.4 %; Level A), 3 with ERBB amplifications (1.3 %; Level B), and 88 cases (39.5 %) with alterations such as CDK4 amplification, PTEN deletion/mutation, and others (Level C). Co-occurring amplifications of KIT, KDR, and PDGFRA at the 4q12 locus were found in 8 cases (3.6 %), while VEGFA and CCND3 co-amplifications at the 6p12-21 locus were seen in 33 cases (14.8 %). These gene amplifications, also reported in US studies, are targetable by multi-kinase inhibitors, although the C-CAT cohort's profiles differed from US cohorts like MSK-IMPACT.

CONCLUSIONS

Precision medicine for rare tumors still poses challenges. In this Japanese cohort, 42.2 % of high-grade OSs had potentially actionable alterations per CKDB. Concurrent gene amplifications of KIT, KDR, and PDGFRA at 4q12, and VEGFA and CCND3 at 6p12-21, might offer promising therapeutic options for patients with recurrent/metastatic OS resistant to conventional chemotherapy.

Targeted RNA Sequencing of Head and Neck Adenoid Cystic Carcinoma Reveals SEC16A::NOTCH1 Fusion and MET Exon 14 Skipping as Potentially Actionable Alterations

PURPOSE

Adenoid cystic carcinoma (AdCC) of the head and neck harbors MYB/MYBL1::NFIB fusions in around 60% of cases, with unfavorable long-term survival due to frequent recurrences and metastases, currently lacking effective targeted therapy. The study aims to identify actionable alterations and to elucidate the molecular underpinnings of MYB/MYBL1::NFIB-negative AdCC using a large targeted RNA sequencing panel.

METHODS AND RESULTS

We retrospectively searched our MSK-Solid Fusion clinical sequencing database for head and neck AdCC sequenced between 2016 and 2023. Of a total of 55 cases, 28 showed MYB::NFIB, 7 showed MYBL1::NFIB, and one case each harbored MYB::MPDZ (case 1) and FUS::MYB (case 2). One base of tongue tumor expressed both MYB::NFIB fusion and MET exon 14 skipping transcripts due to concurrent MET splice site mutation, D1010N (case 3). One parotid tumor lacked MYB/MYBL1 rearrangement but instead showed an in-frame SEC16A::NOTCH1 fusion that preserved the secretase cleavage site (case 4). Clinical records on 4 cases with non-canonical sequencing findings were reviewed. Distant metastases were present at the initial diagnosis (case 2) or at recurrence (cases 1, 3, and 4). Disease-related mortality occurred in cases 2 and 4 despite radiotherapy and immunotherapy.

CONCLUSIONS

The study improved the understanding of AdCC providing the first documentation of tumor clinical behavior associated with MYB::MPDZ and FUS::MYB fusions and reporting potentially actionable SEC16A::NOTCH1 fusion and MET exon 14 skipping mutation. Further research is needed to explore the therapeutic utility of MET inhibition and the efficacy of γ-secretase inhibitors against rare NOTCH1 fusions in AdCC.

Expert consensus on the diagnosis and treatment of solid tumors with BRAF mutations

The BRAF gene is an important signaling molecule in human cells that is involved in the regulation of cell growth, differentiation, and survival. When the BRAF gene mutates, it can lead to abnormal activation of the signaling pathway, which promotes cell proliferation, inhibits cell apoptosis, and ultimately contributes to the occurrence and development of cancer. BRAF mutations are widely present in various cancers, including malignant melanoma, thyroid cancer, colorectal cancer, non-small cell lung cancer, and hairy cell leukemia, among others. BRAF is an important target for the treatment of various solid tumors, and targeted combination therapies, represented by BRAF inhibitors, have become one of the main treatment modalities for a variety of BRAF-mutation-positive solid tumors. Dabrafenib plus trametinib, as the first tumor-agnostic therapy, has been approved by the US Food and Drug Administration for the treatment of adult and pediatric patients aged 6 years and older harboring a BRAF V600E mutation with unresectable or metastatic solid tumors that have progressed following prior treatment and who have no satisfactory alternative treatment options. This is also the first time a BRAF/MEK inhibitor combination has been approved for use in pediatric patients. As research into the diagnosis and treatment of BRAF mutations advances, standardizing the detection of BRAF mutations and the clinical application of BRAF inhibitors becomes increasingly important. Therefore, we have established a universal and systematic strategy for diagnosing and treating solid tumors with BRAF mutations. In this expert consensus, we (1) summarize the epidemiology and clinical characteristics of BRAF mutations in different solid tumors, (2) provide recommendations for the selection of genetic testing methods and platforms, and (3) establish a universal strategy for the diagnosis and treatment of patients with solid tumors harboring BRAF mutations.

Actionable Structural Variant Detection via RNA-NGS and DNA-NGS in Patients With Advanced Non-Small Cell Lung Cancer

Importance

The National Comprehensive Cancer Network (NCCN) guidelines for non-small cell lung cancer suggest that RNA next-generation sequencing (NGS) may improve the detection of fusions and splicing variants compared with DNA-NGS alone. However, there is limited adoption of RNA-NGS in routine oncology clinical care today.

Objective

To analyze clinical evidence from a diverse cohort of patients with advanced lung adenocarcinoma and compare the detection of NCCN-recommended actionable structural variants (aSVs; fusions and splicing variants) via concurrent DNA and RNA-NGS vs DNA-NGS alone.

Design, Setting, and Participants

This multisite, retrospective cohort study examined patients sequenced between February 2021 and October 2023 within the deidentified, Tempus multimodal database, consisting of linked molecular and clinical data. Participants included patients with advanced lung adenocarcinoma and sufficient tissue sample quantities for both RNA-NGS and DNA-NGS testing.

Exposures

Received results from RNA-NGS and DNA-NGS solid-tissue profiling assays.

Main Outcomes and Measures

Detection rates of NCCN guideline-based structural variants (ALK, ROS1, RET and NTRK1/2/3 fusions, as well as MET exon 14 skipping splicing alterations) found uniquely by RNA-NGS.

Results

In the evaluable cohort of 5570 patients, median (IQR) age was 67.8 (61.3-75.4) years, and 2989 patients (53.7%) were female. The prevalence of actionable structural variants detected by either RNA-NGS or DNA-NGS was 8.8% (n = 491), with 86.7% (n = 426) of these detected by DNA-NGS. Concurrent RNA-NGS and DNA-NGS identified 15.3% more patients harboring aSVs compared with DNA-NGS alone (491 vs 426 patients, respectively), including 14.3% more patients harboring actionable fusions (376 vs 329 patients) and 18.6% more patients harboring MET exon 14 skipping alterations (115 vs 97 patients). There was no significant association between the assay used for aSV detection and aSV-targeted therapeutic adoption or clinical outcome. Emerging structural variants (eSVs) were found to have a combined prevalence to be 0.7%, with only 47.5% of eSVs detected by DNA-NGS.

Conclusions and Relevance

In this cohort study, the detection of structural variants via concurrent RNA-NGS and DNA-NGS was higher across multiple NCCN-guideline recommended biomarkers compared with DNA-NGS alone, suggesting that RNA-NGS should be routinely implemented in the care of patients with advanced NSCLC.

Comparison of Results from Two Commercially Available In-House Tissue-Based Comprehensive Genomic Profiling Solutions: Research Use Only AVENIO Tumor Tissue Comprehensive Genomic Profiling Kit and TruSight Oncology 500 Assay

Increased adoption of personalized medicine has brought comprehensive genomic profiling (CGP) to the forefront. However, differences in assay, bioinformatics, and reporting systems and lack of understanding of their complex interplay are a challenge for implementation and achieving uniformity in CGP testing. Two commercially available, tissue-based, in-house CGP assays were compared, in combination with a tertiary analysis solution in a research use only (RUO) context: the AVENIO Tumor Tissue CGP RUO Kit paired with navify Mutation Profiler (RUO) software and the TruSight Oncology 500 RUO assay paired with PierianDx Clinical Genomics Workspace software. Agreements and differences between the assays were assessed for short variants, copy number alterations, rearrangements, tumor mutational burden, and microsatellite instability, including variant categorization and clinical trial-matching (CTM) recommendations. Results showed good overall agreement for short variant, known gene fusion, and microsatellite instability detection. Important differences were obtained in tumor mutational burden scoring, copy number alteration detection, and CTM. Differences in variant and biomarker detection could be explained by bioinformatic approaches to variant calling, filtering, tiering, and normalization; differences in CTM, by underlying reported variants and conceptual differences in system parameters. Thus, distinctions between different approaches may lead to inconsistent results. Complexities in calling, filtering, and interpreting variants illustrate key considerations for implementation of any high-quality CGP in the laboratory and bringing uniformity to genomic insight results.

HER2 Antibody-Drug Conjugates Are Active against Desmoplastic Small Round Cell Tumor

PURPOSE

Desmoplastic small round cell tumor (DSRCT) is a rare but highly aggressive soft tissue sarcoma that arises in the abdominopelvic cavity of young males. Since the discovery of EWSR1::WT1 fusion as the driver of DSRCT, no actionable genomic alterations have been identified, limiting disease management to a combination of surgery, chemotherapy, and radiation, with very poor outcomes. Herein, we evaluated ERBB2/HER2 expression in DSRCT as a therapeutic target.

EXPERIMENTAL DESIGN

ERBB2/HER2 expression was assessed in clinical samples and patient-derived xenografts (PDX) using RNA sequencing, RT-qPCR, and a newly developed HER2 IHC assay (clone 29D8). Responses to HER2 antibody-drug conjugates (ADC)-trastuzumab deruxtecan (T-DXd) and trastuzumab emtansine-were evaluated in DSRCT PDX, cell line, and organoid models. Drug internalization was demonstrated by live microscopy. Apoptosis was evaluated by Western blotting and caspase activity assays.

RESULTS

ERBB2/HER2 was detectable in DSRCT samples from patients and PDXs, with higher sensitivity RNA assays and improved IHC detectability using clone 29D8. Treatment of ERBB2/HER2-expressing DSRCT PDX, cell line, and organoid models with T-DXd or trastuzumab emtansine resulted in tumor regression. This therapeutic response was long-lasting in T-DXd-treated xenografts and was mediated by rapid HER2 ADC complex internalization and cytotoxicity, triggering p53-mediated apoptosis and growth arrest. Xenograft regression was associated with bystander payload effects triggering global tumor niche responses proportional to HER2 status.

CONCLUSIONS

ERBB2/HER2 is a therapeutic target in DSRCT. HER2 ADCs may represent novel options for managing this exceptionally aggressive sarcoma, possibly fulfilling an urgent and historically unmet need for more effective clinical therapy.

NRG1 Fusions in NSCLC: Being eNRGy Conscious

Fusions in neuregulin 1 (NRG1) are rare oncogenic drivers that occur across a number of tumor types, including non-small cell lung cancer (NSCLC). NRG1 has an EGF-like domain that serves as a ligand for HER3 receptors, inducing heterodimerization, usually with HER2, and subsequent activation of oncogenic downstream signaling pathways. Emerging evidence suggests that NSCLC harboring NRG1 fusions do not respond as well to standard therapeutic options including chemotherapy and immunotherapy, and prognosis is poor. Novel treatment approaches targeting the HER2/HER3 pathway are under investigation. Here, we discuss the biology and detection of NRG1 fusions in NSCLC and promising targeted treatment strategies for tumors harboring the mutation.

Molecular profiling METex14+ non-small cell lung cancer (NSCLC): Impact of histology

OBJECTIVES

MET exon 14 skipping alterations (METex14+) represent a heterogeneous subgroup of non-small cell lung cancer (NSCLC) with distinct biological and genomic features. We characterized this heterogeneity in a large cohort, integrating genomic and transcriptomic profiling with clinical outcomes, to elucidate the histologic and molecular traits and survival patterns of METex14+ NSCLC.

MATERIALS AND METHODS

NSCLC tissue samples (n = 28,739) underwent DNA-based next-generation sequencing (592 genes, NextSeq) or whole-exome sequencing (NovaSeq), RNA-sequencing including whole transcriptome sequencing (WTS, NovaSeq), and PD-L1 IHC (Dako 22C3) at Caris Life Sciences. Immune cell fractions were estimated from bulk RNA sequencing (quanTIseq). Real-world survival data (mOS) was calculated from insurance claims. Statistical analyses employed Chi-square, Fisher's exact, or Mann-Whitney U and log-rank tests and were corrected for hypothesis testing where applicable.

RESULTS

A total of 711 METex14+ cases were detected. Of 575 cases of defined histology, 77 (13.6 %) were squamous (Sq), 474 (82.3 %) were nSq (non-squamous), and 24 (4.1 %) were adenosquamous. Mutations in POT1 and BRCA2 were enriched, and amplifications in MDM2, HMGA2, CDK4, and MET were common in METex14+ tumors. TMB-high and TP53 mutated tumors were reduced in METex14+ independent of histology. KEAP1 (2.1 vs 14.7 %) and STK11 mutations (0.8 vs 17.1 %) were reduced only in METex14+ nSq (vs METex14+ Sq, q < 0.05). While the prevalence of PD-L1 high tumors was enriched in METex14+ independent of histology, T-cell inflamed tumors were enriched only in nSq METex14+. B-cells and CD8+ T-cells (1.07-1.43-fold) were enriched in nSq METex14+, and dendritic cells (0.32 fold) were reduced only in METex14+ Sq. METex14+ tumors had a modest improvement in mOS compared to METex14- tumors (mOS = 22.9 m vs 18.6 m, HR = 0.914, p = 0.04). Moreover, METex14+ tumors who received immunotherapy (IO) had a modest improvement in survival (mOS = 27.5 m vs 21.8 m; HR = 0.803, p = 0.03) compared to those who did not receive IO. METex14+ nSq tumors were associated with improved mOS compared to METex14+ Sq tumors (mOS = 27.7 vs 8.9 m, HR = 0.493, p < 0.0001).

CONCLUSION

METex14+ alterations are a heterogeneous subgroup of NSCLC. Our analysis reveals that METex14+ nSq exhibit improved survival compared to METex14+ Sq. The distinct genomic and transcriptomic variations across histologies warrant clinical consideration.

Tumor-Agnostic Genomic and Clinical Analysis of BRAF Fusions Identifies Actionable Targets

PURPOSE

Even though BRAF fusions are increasingly detected in standard multigene next-generation sequencing panels, few reports have explored their structure and impact on clinical course.

EXPERIMENTAL DESIGN

We collected data from patients with BRAF fusion-positive cancers identified through a genotyping protocol of 97,024 samples. Fusions were characterized and reviewed for oncogenic potential (in-frame status, non-BRAF partner gene, and intact BRAF kinase domain).

RESULTS

We found 241 BRAF fusion-positive tumors from 212 patients with 82 unique 5' fusion partners spanning 52 histologies. Thirty-nine fusion partners were not previously reported, and 61 were identified once. BRAF fusion incidence was enriched in pilocytic astrocytomas, gangliogliomas, low-grade neuroepithelial tumors, and acinar cell carcinoma of the pancreas. Twenty-four patients spanning multiple histologies were treated with MAPK-directed therapies, of which 20 were evaluable for RECIST. Best response was partial response (N = 2), stable disease (N = 11), and progressive disease (N = 7). The median time on therapy was 1 month with MEK plus BRAF inhibitors [(N = 11), range 0-18 months] and 8 months for MEK inhibitors [(N = 14), range 1-26 months]. Nine patients remained on treatment for longer than 6 months [pilocytic astrocytomas (N = 6), Erdheim-Chester disease (N = 1), extraventricular neurocytoma (N = 1), and melanoma (N = 1)]. Fifteen patients had acquired BRAF fusions.

CONCLUSIONS

BRAF fusions are found across histologies and represent an emerging actionable target. BRAF fusions have a diverse set of fusion partners. Durable responses to MAPK therapies were seen, particularly in pilocytic astrocytomas. Acquired BRAF fusions were identified after targeted therapy, underscoring the importance of postprogression biopsies to optimize treatment at relapse in these patients.

RET Inhibitors in RET Fusion-Positive Lung Cancers: Past, Present, and Future

While activating RET fusions are identified in various cancers, lung cancer represents the most common RET fusion-positive tumor. The clinical drug development of RET inhibitors in RET fusion-positive lung cancers naturally began after RET fusions were first identified in patient tumor samples in 2011, and thereafter paralleled drug development in RET fusion-positive thyroid cancers. Multikinase inhibitors were initially tested with limited efficacy and substantial toxicity. RET inhibitors were then designed with improved selectivity, central nervous system penetrance, and activity against RET fusions and most RET mutations, including resistance mutations. Owing their success to these rationally designed features, the first-generation selective RET tyrosine kinase inhibitors (TKIs) had higher response rates, more durable disease control, and an improved safety profile compared to the multikinase inhibitors. This led to lung and thyroid cancer, and later tumor-agnostic regulatory approvals. While next-generation RET TKIs were designed to abrogate uncommon on-target (e.g., solvent front mutation) resistance to selpercatinib and pralsetinib, many of these drugs lacked the selectivity of the first-generation TKIs, raising the question of what the future holds for drug development in RET-dependent cancers.

Precision Medicine in Cytopathology

Over the last decade, cancer diagnostics has undergone a notable transformation with increasing complexity. Minimally invasive diagnostic tests, driven by advanced imaging and early detection protocols, are redefining patient care and reducing the need for more invasive procedures. Modern cytopathologists now safeguard patient samples for vital biomarker and molecular testing. In this article, we explore ancillary testing modalities and the role of biomarkers in organ-specific contexts, underscoring the transformative impact of precision medicine. Finally, the advent of more than 80 Food and Drug Administration-approved predictive biomarkers signals a new era, guiding cancer care toward personalized and targeted strategies.

Non-Small-Cell Lung Cancers (NSCLCs) Harboring RET Gene Fusion, from Their Discovery to the Advent of New Selective Potent RET Inhibitors: "Shadows and Fogs"

RET fusions are relatively rare in Non-Small-Cell Lung Cancers (NSCLCs), being around 1-2% of all NSCLCs. They share the same clinical features as the other fusion-driven NSCLC patients, as follows: younger age, adenocarcinoma histology, low exposure to tobacco, and high risk of spreading to the brain. Chemotherapy and immunotherapy have a low impact on the prognosis of these patients. Multitargeted RET inhibitors have shown modest activity jeopardized by high toxicity. New potent and selective RET inhibitors (RET-Is) (pralsetinib and selpercatinib) have achieved a higher efficacy minimizing the known toxicities of the multitargeted agents. This review will describe the sensitivity of immune-checkpoint inhibitors (ICIs) in RET fusion + NSCLC patients, as well their experiences with the 'old' multi-targeted RET inhibitors. This review will focus on the advent of new potent and selective RET-Is. We will describe their efficacy as well as the main mechanisms of resistance to them. We will further proceed to deal with the new drugs and strategies proposed to overcome the resistance to RET-Is. In the last section, we will also focus on the safety profile of RET-Is, dealing with the main toxicities as well as the rare but severe adverse events.

Unusual presentation of ROS1 rearranged metastatic non-small cell lung cancer

The spectrum of clinical and radiographic presentations of lung adenocarcinoma is increasingly broad, including in the metastatic setting. Here, we report on a patient who initially presented with a mild chronic cough that remained stable over a decade, with serial CT scans showing gradual worsening of multifocal areas of consolidation and ground-glass opacities of the bilateral lungs. The patient was ultimately diagnosed with ROS1 rearranged lung adenocarcinoma and achieved a dramatic response with entrectinib. This case highlights the variable presentation of non-small cell lung cancer (NSCLC) and the importance of comprehensive molecular testing for newly diagnosed metastatic NSCLC.

Successive next-generation sequencing strategy for optimal fusion gene detection in non-small-cell lung cancer in clinical practice

Metastatic non-small-cell lung cancer (NSCLC) displays various molecular alterations in the RAS-MAPK pathway. In particular, NSCLCs show high rates of targetable gene fusion in ALK, RET, ROS1, NRG1 and NTRK, or MET exon 14 skipping. Rapid and accurate detection of gene fusion in EGFR/KRAS/BRAF mutations is important for treatment selection especially for first-line indications. RNA-based next-generation sequencing (NGS) panels appear to be the most appropriate as all targets are multiplexed in a single run. While comprehensive NGS panels remain costly for daily practice, optimal sequencing strategies using targeted DNA/RNA panel approaches need to be validated. Here, we describe our lung cancer screening strategy using DNA and RNA targeted approaches in a real-life cohort of 589 NSCLC patients assessed for molecular testing. Gene fusions were analysed in 174 patients negative for oncogene driver mutations or ALK immunohistochemistry in a two-step strategy. Targetable alterations were identified in 28% of contributive samples. Non-smokers had a 63.7% probability to have a targetable alteration as compared to 21.5% for smokers. Overall survival was significantly higher (p=0.03) for patients who received a molecularly matched therapy. Our study shows the feasibility in routine testing of NSCLC DNA/RNA molecular screening for all samples in a cost- and time-controlled manner. The significant high fusion detection rate in patients with wild-type RAS-MAPK tumours highlights the importance of amending testing strategies in NSCLC.

Fusion Challenges in Solid Tumors: Shaping the Landscape of Cancer Care in Precision Medicine

Targeting actionable fusions has emerged as a promising approach to cancer treatment. Next-generation sequencing (NGS)-based techniques have unveiled the landscape of actionable fusions in cancer. However, these approaches remain insufficient to provide optimal treatment options for patients with cancer. This article provides a comprehensive overview of the actionability and clinical development of targeted agents aimed at driver fusions. It also highlights the challenges associated with fusion testing, including the evaluation of patients with cancer who could potentially benefit from testing and devising an effective strategy. The implementation of DNA NGS for all tumor types, combined with RNA sequencing, has the potential to maximize detection while considering cost effectiveness. Herein, we also present a fusion testing strategy aimed at improving outcomes in patients with cancer.

Fusion Genes Landscape of Lung Cancer Patients From Inner Mongolia, China

Lung cancer is the leading cause of cancer-related deaths globally. Gene fusion, a key driver of tumorigenesis, has led to the identification of numerous driver gene fusions for lung cancer diagnosis and treatment. However, previous studies focused on Western populations, leaving the possibility of unrecognized lung cancer-associated gene fusions specific to Inner Mongolia due to its unique genetic background and dietary habits. To address this, we conducted DNA sequencing analysis on tumor and adjacent nontumor tissues from 1200 individuals with lung cancer in Inner Mongolia. Our analysis established a comprehensive fusion gene landscape specific to lung cancer in Inner Mongolia, shedding light on potential region-specific molecular mechanisms underlying the disease. Compared to Western cohorts, we observed a higher occurrence of ALK and RET fusions in Inner Mongolian patients. Additionally, we discovered eight novel fusion genes in three patients: SLC34A2-EPHB1, CCT6P3-GSTP1, BARHL2-APC, HRAS-MELK, FAM134B-ERBB2, ABCB1-GIPC1, GPR98-ALK, and FAM134B-SALL1. These previously unreported fusion genes suggest potential regional specificity. Furthermore, we characterized the fusion genes' structures based on breakpoints and described their impact on major functional gene domains. Importantly, the identified novel fusion genes exhibited significant clinical and pathological relevance. Notably, patients with SLC34A2-EPHB1, CCT6P3-GSTP1, and BARHL2-APC fusions showed sensitivity to the combination of chemotherapy and immunotherapy. Patients with HRAS-MELK, FAM134B-ERBB2, and ABCB1-GIPC1 fusions showed sensitivity to chemotherapy. In summary, our study provides novel insights into the frequency, distribution, and characteristics of specific fusion genes, offering valuable guidance for the development of effective clinical treatments, particularly in Inner Mongolia.

Clinical practice recommendations for the use of next-generation sequencing in patients with solid cancer: a joint report from KSMO and KSP

In recent years, next-generation sequencing (NGS)-based genetic testing has become crucial in cancer care. While its primary objective is to identify actionable genetic alterations to guide treatment decisions, its scope has broadened to encompass aiding in pathological diagnosis and exploring resistance mechanisms. With the ongoing expansion in NGS application and reliance, a compelling necessity arises for expert consensus on its application in solid cancers. To address this demand, the forthcoming recommendations not only provide pragmatic guidance for the clinical use of NGS but also systematically classify actionable genes based on specific cancer types. Additionally, these recommendations will incorporate expert perspectives on crucial biomarkers, ensuring informed decisions regarding circulating tumor DNA panel testing.

Clinical Practice Recommendations for the Use of Next-Generation Sequencing in Patients with Solid Cancer: A Joint Report from KSMO and KSP

In recent years, next-generation sequencing (NGS)-based genetic testing has become crucial in cancer care. While its primary objective is to identify actionable genetic alterations to guide treatment decisions, its scope has broadened to encompass aiding in pathological diagnosis and exploring resistance mechanisms. With the ongoing expansion in NGS application and reliance, a compelling necessity arises for expert consensus on its application in solid cancers. To address this demand, the forthcoming recommendations not only provide pragmatic guidance for the clinical use of NGS but also systematically classify actionable genes based on specific cancer types. Additionally, these recommendations will incorporate expert perspectives on crucial biomarkers, ensuring informed decisions regarding circulating tumor DNA panel testing.

Recommendations for the use of next-generation sequencing (NGS) for patients with advanced cancer in 2024: a report from the ESMO Precision Medicine Working Group

BACKGROUND

Advancements in the field of precision medicine have prompted the European Society for Medical Oncology (ESMO) Precision Medicine Working Group to update the recommendations for the use of tumour next-generation sequencing (NGS) for patients with advanced cancers in routine practice.

METHODS

The group discussed the clinical impact of tumour NGS in guiding treatment decision using the ESMO Scale for Clinical Actionability of molecular Targets (ESCAT) considering cost-effectiveness and accessibility.

RESULTS

As for 2020 recommendations, ESMO recommends running tumour NGS in advanced non-squamous non-small-cell lung cancer, prostate cancer, colorectal cancer, cholangiocarcinoma, and ovarian cancer. Moreover, it is recommended to carry out tumour NGS in clinical research centres and under specific circumstances discussed with patients. In this updated report, the consensus within the group has led to an expansion of the recommendations to encompass patients with advanced breast cancer and rare tumours such as gastrointestinal stromal tumours, sarcoma, thyroid cancer, and cancer of unknown primary. Finally, ESMO recommends carrying out tumour NGS to detect tumour-agnostic alterations in patients with metastatic cancers where access to matched therapies is available.

CONCLUSION

Tumour NGS is increasingly expanding its scope and application within oncology with the aim of enhancing the efficacy of precision medicine for patients with cancer.

[A Case of EML4-ALK Fusion V1 Subtype Lung Adenocarcinoma Detected by RNA-based NGS]

Lung cancer is the malignant tumor with the highest incidence and mortality rate worldwide. For lung adenocarcinoma, identifying specific gene mutations, fusions, and giving corresponding targeted drugs can greatly improve the survival time of the patients. Among them, anaplastic lymphoma kinase (ALK) fusion occurs in 3%-7% of non-small cell lung cancer (NSCLC). In clinical practice, a variety of detection methods can be used to determine the ALK fusion status, but false negative test results are possible. This paper retrospectively analyzed the diagnosis and treatment of a patient with lung adenocarcinoma, judged the ALK fusion status by various detection methods. Among them, immunohistochemistry (IHC)(Ventana D5F3), RNA based next-generation sequencing (RNA-based NGS) confirmed positive echinoderm microtubule associated protein like 4 (EML4)-ALK fusion, while DNA-based NGS was negative. This paper analyzed the detection methods of ALK fusion, in order to clarify which detection method is the most accurate and simple to choose in different clinical cases and guide the subsequent treatment.
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Analysis on the pathogenesis and treatment progress of NRG1 fusion-positive non-small cell lung cancer

Lung cancer persistently leads as the primary cause of morbidity and mortality among malignancies. A notable increase in the prevalence of lung adenocarcinoma has become evident in recent years. Although targeted therapies have shown in treating certain subsets of non-small cell lung cancers (NSCLC), a significant proportion of patients still face suboptimal therapeutic outcomes. Neuregulin-1 (NRG1), a critical member of the NRG gene family, initially drew interest due to its distribution within the nascent ventricular endocardium, showcasing an exclusive presence in the endocardium and myocardial microvessels. Recent research has highlighted NRG1's pivotal role in the genesis and progression across a spectrum of tumors, influencing molecular perturbations across various tumor-associated signaling pathways. This review provides a concise overview of NRG1, including its expression patterns, configuration, and fusion partners. Additionally, we explore the unique features and potential therapeutic strategies for NRG1 fusion-positive occurrences within the context of NSCLC.

Shifting from Immunohistochemistry to Screen for ALK Rearrangements: Real-World Experience in a Large Single-Center Cohort of Patients with Non-Small-Cell Lung Cancer

The identification of ALK fusions in advanced non-small-cell lung carcinoma (aNSCLC) is mandatory for targeted therapy. The current diagnostic approach employs an algorithm using ALK immunohistochemistry (IHC) screening, followed by confirmation through ALK FISH and/or next-generation sequencing (NGS). Challenges arise due to the infrequency of ALK fusions (3-7% of aNSCLC), the suboptimal specificity of ALK IHC and ALK FISH, and the growing molecular demands placed on small tissue samples, leading to interpretative, tissue availability, and time-related issues. This study investigates the effectiveness of RNA NGS as a reflex test for identifying ALK fusions in NSCLC, with the goal of replacing ALK IHC in the systematic screening process. The evaluation included 1246 NSCLC cases using paired techniques: ALK IHC, ALK FISH, and ALK NGS. ALK IHC identified 51 positive cases (4%), while RNA NGS detected ALK alterations in 59 cases (4.8%). Of the 59 ALK-positive cases identified via NGS, 53 (89.8%) were confirmed to be positive. This included 51 cases detected via both FISH and IHC, and 2 cases detected only via FISH, as they were completely negative according to IHC. The combined reporting time for ALK IHC and ALK FISH averaged 13 days, whereas ALK IHC and RNA NGS reports were obtained in an average of 4 days. These results emphasize the advantage of replacing systematic ALK IHC screening with RNA NGS reflex testing for a more comprehensive and accurate assessment of ALK status.

Serial Cell-Free DNA Sequencing in ROS1 Fusion-Positive Lung Cancers During Treatment With Entrectinib

PURPOSE

Patients with metastatic ROS1 fusion-positive non-small cell lung cancer (NSCLC) are effectively treated with entrectinib, a multikinase inhibitor. Whether serial targeted gene panel sequencing of cell-free DNA (cfDNA) can identify response and progression along with mechanisms of acquired resistance to entrectinib is underexplored.

METHODS

In patients with ROS1 fusion-positive NSCLC, coclinical trial plasma samples were collected before treatment, after two cycles, and after progression on entrectinib (global phase II clinical trial, ClinicalTrials.gov identifier: NCT02568267). Samples underwent cfDNA analysis using MSK-ACCESS. Variant allele frequencies of detectable alterations were correlated with objective response per RECIST v1.1 criteria.

RESULTS

Twelve patients were included, with best response as partial response (n = 9, 75%), stable disease (n = 2, 17%), and progressive disease (PD; n = 1, 8%). A ROS1 fusion was variably detected in cfDNA; however, patients without a ROS1 fusion in cfDNA had no other somatic alterations detected, indicative of possible low cfDNA shedding. Clearance of the enrolling ROS1 fusion or concurrent non-ROS1 alterations (TP53, CDH1, NF1, or ARID1A mutations) was observed in response to entrectinib therapy. Radiologic PD was accompanied by redemonstration of a ROS1 fusion or non-ROS1 alterations. On-target resistance was rare; only one patient acquired ROS1 G2032R at the time of progression. Several patients acquired new off-target likely oncogenic alterations, including a truncating alteration in NF1.

CONCLUSION

Serial cfDNA monitoring may complement radiographic assessments as determinants of response and resistance to entrectinib in ROS1 fusion-positive lung cancers in addition to detecting putative resistance mechanisms on progression.

Basket Trials: Past, Present, and Future

Large-scale tumor molecular profiling has revealed that diverse cancer histologies are driven by common pathways with unifying biomarkers that can be exploited therapeutically. Disease-agnostic basket trials have been increasingly utilized to test biomarker-driven therapies across cancer types. These trials have led to drug approvals and improved the lives of patients while simultaneously advancing our understanding of cancer biology. This review focuses on the practicalities of implementing basket trials, with an emphasis on molecularly targeted trials. We examine the biologic subtleties of genomic biomarker and patient selection, discuss previous successes in drug development facilitated by basket trials, describe certain novel targets and drugs, and emphasize practical considerations for participant recruitment and study design. This review also highlights strategies for aiding patient access to basket trials. As basket trials become more common, steps to ensure equitable implementation of these studies will be critical for molecularly targeted drug development.

The Importance of Biomarker Testing in the Treatment of Advanced Non-Small Cell Lung Cancer: A Podcast

The identification of actionable biomarkers and development of targeted therapies have revolutionized the field of lung cancer treatment. In patients with advanced non-small cell lung cancer (NSCLC), biomarker testing can inform selection of effective targeted therapies as well as avoid therapies that are less likely to be effective in certain populations. A growing number of actionable targets, including those involving EGFR, ALK, ROS1, BRAF, MET, KRAS, NTRK, RET, HER2, and PD-L1, can be identified with biomarker testing. More than half of patients with advanced NSCLC have tumors that harbor genetic alterations that can be targeted. When these patients are treated with targeted therapy, survival and quality of life may be significantly improved. In addition, broad-based molecular testing may detect alterations identifying patients who are potentially eligible for current or future clinical trials. Comprehensive biomarker testing rates in communities are often low, and turnaround times for results can be unacceptably long. There is an unmet need for widespread, efficient, and routine testing of all biomarkers recommended by clinical guidelines. New testing techniques and technologies can make this an attainable goal. Panel-based sequencing platforms are becoming more accessible, and molecular biomarker analysis of circulating tumor DNA is becoming more common. In this podcast, we discuss the importance of biomarker testing in advanced NSCLC and explore topics such as testing methodologies, effect of biomarker testing on patient outcomes, emerging technologies, and strategies for improving testing rates in the United States. Supplementary file1 (MP4 121301 KB).

Expanding the Spectrum of NR4A3 Fusion-Positive Gynecologic Leiomyosarcomas

Recurrent gene fusions have been observed in epithelioid and myxoid variants of uterine leiomyosarcoma. PGR::NR4A3 fusions were recently described in a subset of epithelioid leiomyosarcomas exhibiting rhabdoid morphology. In this study, we sought to expand the clinical, morphologic, immunohistochemical, and genetic features of gynecologic leiomyosarcomas harboring NR4A3 rearrangements with PGR and novel fusion partners. We identified 9 gynecologic leiomyosarcomas harboring PGR::NR4A3, CARMN::NR4A3, ACTB::NR4A3, and possible SLCO5A1::NR4A3 fusions by targeted RNA sequencing. Tumors frequently affected premenopausal women, involving the uterine corpus, uterine cervix, or pelvis. All were similarly characterized by lobules of monomorphic epithelioid and/or spindled cells arranged in sheets, cords, trabeculae, and micro- and macrocysts associated with abundant myxoid matrix and hemorrhage, creating labyrinth-like or pulmonary edema-like architecture. Myogenic differentiation with frequent estrogen receptor and progesterone receptor staining and no CD10 expression characterized all tumors. All cases showed high NR4A3 RNA expression levels and NOR1 (NR4A3) nuclear staining similar to salivary gland acinic cell carcinomas and a subset of extraskeletal myxoid chondrosarcomas harboring NR4A3 rearrangements. NOR1 (NR4A3) immunohistochemistry may serve as a useful diagnostic marker of NR4A3 fusion-positive gynecologic leiomyosarcomas.

RET Fusion Testing in Patients With NSCLC: The RETING Study

Introduction

RET inhibitors with impressive overall response rates are now available for patients with NSCLC, yet the identification of RET fusions remains a difficult challenge. Most guidelines encourage the upfront use of next-generation sequencing (NGS), or alternatively, fluorescence in situ hybridization (FISH) or reverse transcriptase-polymerase chain reaction (RT-PCR) when NGS is not possible or available. Taken together, the suboptimal performance of single-analyte assays to detect RET fusions, although consistent with the notion of encouraging universal NGS, is currently widening some of the clinical practice gaps in the implementation of predictive biomarkers in patients with advanced NSCLC.

Methods

This situation prompted us to evaluate several RET assays in a large multicenter cohort of RET fusion-positive NSCLC (n = 38) to obtain real-world data. In addition to RNA-based NGS (the criterion standard method), all positive specimens underwent break-apart RET FISH with two different assays and were also tested by an RT-PCR assay.

Results

The most common RET partners were KIF5B (78.9%), followed by CCDC6 (15.8%). The two RET NGS-positive but FISH-negative samples contained a KIF5B(15)-RET(12) fusion. The three RET fusions not identified with RT-PCR were AKAP13(35)-RET(12), KIF5B(24)-RET(9) and KIF5B(24)-RET(11). All three false-negative RT-PCR cases were FISH-positive, exhibited a typical break-apart pattern, and contained a very high number of positive tumor cells with both FISH assays. Signet ring cells, psammoma bodies, and pleomorphic features were frequently observed (in 34.2%, 39.5%, and 39.5% of tumors, respectively).

Conclusions

In-depth knowledge of the advantages and disadvantages of the different RET testing methodologies could help clinical and molecular tumor boards implement and maintain sensible algorithms for the rapid and effective detection of RET fusions in patients with NSCLC. The likelihood of RET false-negative results with both FISH and RT-PCR reinforces the need for upfront NGS in patients with NSCLC.