Specific Fusion Genes Research Articles

High-Throughput Hybridization Assay as First-Line Diagnostic Test for Sarcomas: Clinical Assessment in a Tertiary Referral Center.

Sarcomas are rare and highly heterogeneous mesenchymal tumors with deceptive morphologic features that pose a challenge for precise diagnostics. Chromosomal rearrangements generating pathognomonic gene fusions are useful diagnostic markers, traditionally tested using single-plex standard of care assays with limited diagnostic yield. NanoString nCounter technology has emerged as a robust solution with multiplexing capabilities. To optimize NanoString effective coverage of specific entities and conduct a validation study to support its clinical implementation. We reconfigured a NanoString's codeset by including a set of probes for detecting gene fusion variants of solitary fibrous tumors, low-grade fibromyxoid sarcomas/sclerosing epithelioid fibrosarcomas, and undifferentiated small round cell sarcomas, totaling 188 probes. A technical validation study was conducted with 96 retrospective samples. Additionally, 76 prospective samples were evaluated to assess the assay's clinical performance. Both technical and clinical validation studies showed that NanoString's codeset reached >88% sensitivity and 100% specificity, compared with standard of care methods, and superior diagnostic yield as a first-line test. Our design enabled the detection of almost all fusion variants of NGFI-A binding protein 2 (NAB2) with signal transducer and activator of transcription 6 (STAT6) in solitary fibrous tumors, as well as cAMP responsive element binding protein 3 like 1/2 (CREB3L1/2) rearrangements in all low-grade fibromyxoid sarcoma/sclerosing epithelioid fibrosarcoma cases. Identification of specific gene fusions of undifferentiated small round cell sarcoma was also improved, but additional strategies are necessary to attain full coverage. The NanoString platform demonstrated good sensitivity, specificity, and superior diagnostic yield. It is a cost-effective assay with rapid turnaround time, low sample consumption, streamlined analysis, and easy customization. Therefore, it is a promising alternative first-line diagnostic tool for routine sarcoma testing.

Clinical and Technical Validation of OncoIndx® Assay-A Comprehensive Genome Profiling Assay for Pan-Cancer Investigations.

Comprehensive next-generation sequencing (NGS) assays enable the identification of clinically relevant mutations, enhancing the capability for targeted therapeutic interventions. In addition, genomic alterations driving the oncogenic roadmap and leading to resistance mechanisms are reshaping precision oncology. We report the workflow and clinical and technical validation of the OncoIndx® NGS platform-a comprehensive genomic profiling (CGP)-based assay for pan-cancer investigation. We evaluated the concordance between the OncoIndx® test findings and clinically established hotspot detection using SeraSeq reference standards. OncoIndx is a hybridization capture-based NGS assay for the targeted deep sequencing of all exons and selected introns of 1080 cancer-related genes. We show the outcome in the form of tier I and tier II single nucleotide variants (SNVs), copy number alterations (CNAs), and specific gene fusions. OncoIndx® also informs genome-wide tumor mutational burden (TMB), microsatellite instability (MSI), homologous recombination deficiency (HRD), and genomic loss of heterozygosity (gLOH). A total of 63 samples were utilized for validation with reference standards, clinical samples, and orthogonal assessment for genomic alterations. In addition, 49 cross-laboratory samples were validated for microsatellite instability (MSI), and for the tumor mutation burden (TMB), 18 samples as reference standards, 6 cross-laboratory samples, and 29 TCGA samples were utilized. We show a maximum clinical sensitivity of 98% and a positive predictive value (PPV) of 100% for the clinically actionable genomic variants detected by the assay. In addition, we demonstrate analytical validation with the performance of the assay, limit of detection (LoD), precision, and orthogonal concordance for various types of SVs, CNAs, genomic rearrangements, and complex biomarkers like TMB, MSI, and HRD. The assay offers reliable genomic predictions with the high-precision detection of actionable variants, validated by established reference standards.

Role of WT1 in Measurable Residual Disease Follow-Up in the Post Allogeneic Stem Cell Transplant Setting.

Objectives: The Wilms' tumor gene 1 (WT1) plays a critical role in cell development and the regulation of essential genes involved in cell growth and metabolism. In the context of hematopoietic tumors, including acute myeloid leukemia (AML), WT1 has been identified as a potential marker for measurable residual disease (MRD) assessment. Relapse after allogeneic hematopoietic stem cell transplantation (allo-SCT) remains a significant challenge in AML treatment, highlighting the importance of MRD monitoring for risk stratification and treatment decisions. This study aimed to investigate the clinical significance of WT1 as a molecular marker for MRD and its correlation with chimerism in AML patients post-allo-SCT setting. Methods: We have included 58 patients with WT1-expression-positive acute myeloid leukemia (AML) who received allo-SCT in our center between 2016-2022. The exclusion criteria are as follows: not having WT1 polymerase chain reaction (PCR) measurement at diagnosis, not receiving allo-SCT, and not having a serial measurement of WT1 post-transplant. Pre- and post-transplant assessments were made with flow cytometry, WT1 PCR, and bone marrow morphological evaluations. Statistical analyses were carried out to explore correlations between WT1 levels, MRD markers, and chimerism post-transplantation. Results: We found that WT1 had a significant correlation with flow cytometry and bone marrow morphological evaluation, but not with chimerism. Interestingly, high WT1 expressors exhibited a more robust correlation with chimerism compared to the general cohort. The negative predictive value for post-allo-SCT relapse was 91.8% for the whole WT1 cohort; for high WT1 expressors, it was similar, at 87.5%. The negative predictive value for post-allo-SCT relapse was high for the whole WT1 cohort; for high WT1 expressors, it was similar. The WT1 MRD assay showed a high negative predictive value for post-allo-SCT relapse, consistent across both the entire cohort (91.8%) and high WT1 expressors (87.5%). Conclusions: WT1 expression levels may serve as a valuable ancillary marker in MRD assessment and relapse prediction post-allo-SCT in AML patients, particularly for those lacking specific fusion genes or mutations. However, further large-scale, controlled studies are needed to standardize WT1 MRD assays and establish clear guidelines for their clinical application.

Beneath HMGA2 alterations in pleomorphic adenomas: Pathological, immunohistochemical, and molecular insights

AimsMost salivary gland neoplasms are distinguished by specific recurrent gene fusions. Recently, a subset of pleomorphic adenomas (PAs) originated from the parotid gland harboring the HMGA2:WIF1 fusion was described with a canalicular adenoma-like morphology and a greater propensity for recurrence and carcinomatous transformation. Methods and resultsThis study delineates the clinicopathological attributes of 54 cases of PAs exhibiting HMGA2 alterations, predominantly characterized by the HMGA2:WIF1 fusion, alongside a comparative analysis of their morphological and immunohistochemical profiles. The cohort consisted of 23 females and 31 males (n = 54), mean age was 56.7 (25–84), tumors predominantly originated from the parotid gland (94.4%, 51/54), with 3 cases from seromucous glands (5.6%). Mean tumor size was 2.6 cm (0.8–7.5). No clinical difference (demographic, follow-up) was observed among histological subsets (conventional, hybrid, and pure). Complete excision was performed in all cases, with follow-up data available for 41% (22/54) of patients, showing 13.6% of recurrence (3/22) between 5 and 8 months. Various histological growth patterns were identified, with the pure hypercellular monomorphic subset being the most prevalent. The HMGA2:WIF1 gene was identified in all subsets without any particular predominance. Novel gene partners of HMGA2 were identified, comprising NRXN1, INPP4B, MSRB3, PHLDA1, and FLJ41278. ConclusionsThe present study reports that the HMGA2:WIF1 gene fusion was present in all subsets of PAs without significant predominance. However, further investigations are warranted to explore the relationship between histological subsets of PAs and the molecular alterations underlying them.

Single-drug Chemotherapy Plus Immunotherapy as First-line Treatment for Stage Ⅳ Non-small Cell Lung Cancer Elderly Patients: A Phase II Clinical Trial UNICORN Study

IntroductionLung cancer remains the most common malignancy and the leading cancer-related death among the elderly in China, which deserves more research attention. Immunotherapy combined with platinum-based doublet chemotherapy has been approved as the standard treatment for advanced non-small cell lung cancer (NSCLC) patients who are devoid of specific gene mutations or fusions. Given that patients with NSCLC over the age of 65 typically exhibit declining organ function and physical condition, they often showed reduced tolerance for this rigorous treatment regimen. However, the KEYNOTE-042 study illuminated a promising pathway: in patients testing positive for programmed death-ligand 1 (PD-L1), immunotherapy alone has demonstrated a superior overall survival (OS) compared to platinum-based doublet chemotherapy. This suggests that moderating the intensity of chemotherapy and prioritizing immunotherapy may be a gentler alternative in elderly demographic. Patients and MethodsThis multicenter phase II clinical trial named UNICORN aimed to enroll 49 patients aged 65 and older, utilizing paclitaxel or nab-paclitaxel for those with squamous NSCLC, and pemetrexed for those diagnosed with lung adenocarcinoma. The treatment protocol entails 4 cycles of serplulimab plus chemotherapy followed by an extended regimen of serplulimab maintenance, spanning a total of 35 cycles. Primary endpoints of this study are progression-free survival (PFS), disease control rate (DCR) and the secondary endpoints are OS, objective control rate (ORR) and safety metrics. ConclusionThis is the first study to evaluate the efficacy and safety of serplulimab combined with either paclitaxel or pemetrexed in elderly treatment-naïve patients with stage IV NSCLC whose PD-L1 are positive.

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.

Identification of gene fusions associated with amyotrophic lateral sclerosis.

Genetics is an important risk factor for amyotrophic lateral sclerosis (ALS), a neurodegenerative disease affecting motor neurons. Recent findings demonstrate that in addition to specific genetic mutations, structural variants caused by genetic instability can also play a causative role in ALS. Genomic instability can lead to deletions, duplications, insertions, inversions, and translocations in the genome, and these changes can sometimes lead to fusion of distinct genes into a single transcript. Gene fusion events have been studied extensively in cancer; however, they have not been thoroughly investigated in ALS. The aim of this study was to determine whether gene fusions are present in ALS. Gene fusions were identified using STAR Fusion v1.10.0 software in bulk RNA-Seq data from human postmortem samples from publicly available data sets from Target ALS and the New York Genome Center ALS Consortium. We report the presence of gene fusion events in several brain regions as well as in spinal cord samples in ALS. Although most gene fusions were intra-chromosomal events between neighboring genes and present in both ALS and control samples, there was a significantly greater number of unique gene fusions in ALS compared to controls. Lastly, we identified specific gene fusions with a significant burden in ALS, that were absent from both control samples and known cancer gene fusion databases. Collectively, our findings reveal an enrichment of gene fusions in ALS and suggest that these events may be an additional genetic cause linked to ALS pathogenesis.

Impact of HBV Integration on Hepatocellular Carcinoma After Long-Term Antiviral Therapy.

Few studies have reported the integrated characteristics of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) after long-term antiviral therapy. This study aimed to investigate the HBV integration features in HBV-HCC patients who had undergone long-term antiviral therapy, evaluate their impact on clinical indicators, and analyze the potential mechanisms involved. We utilized genome-wide association study (GWAS) to analyze liver cancer tissues and detect the presence of HBV integration. Seventeen patients with HBV integration were included in the integration (Int) group, while the remaining five patients were included in the non-integration (N-int) group. Clinical indicators were regularly monitored and compared between the two groups. The characteristics of HBV integration patterns were analyzed, and differences between the groups were explored at the chromosome and genomic levels. After long-term antiviral therapy, although the frequency of HBV integration in HBV-HCC was reduced, residual HBV integration still accelerated the development of HCC. It affected the diagnosis, treatment, and prognosis of patients. HBV integration events led to changes in chromosome structure, which were closely related to HCC. Novel fusion genes were detected at a high frequency and had the potential to be specific detection sites for HBV-HCC. HBV integration events are synergistically involved in the human genome and HBV, which can lead to chromosome structural instability, gene rearrangement events closely related to HCC production, and the formation of new specific fusion genes.

Insight into NSCLC through novel analysis of gene interactions and characteristics.

Around 80 to 85% of all lung cancers are non-small cell lung cancer (NSCLC). Previous research has aimed at exploring the genetic basis of NSCLC through individual approaches, but studies have yet to investigate the results of combining them. Here we show that analyzing NSCLC genetics through three approaches simultaneously creates unique insights into our understanding of the disease. Through a combination of previous research and bioinformatics tools, we determined 35 NSCLC candidate genes. We analyzed these genes in 3 different approaches. First, we found the gene fusions between these candidate genes. Second, we found the common superfamilies between genes. Finally, we identified mutational signatures that are possibly associated with NSCLC. Each approach has its individual, unique results. Fusion relationships identify specific gene fusion targets, common superfamilies identify possible avenues to determine novel target genes, and identifying NSCLC associated mutational signatures has diagnostic and prognostic benefits. Combining the approaches, we found that gene CD74 has significant fusion relationships, but it has no association with the other two approaches, suggesting that CD74 is associated with NSCLC mainly because of its fusion relationships. Targeting the gene fusions of CD74 may be an alternative NSCLC treatment. This genetic analysis has indeed created unique insight into NSCLC genes. Both the results from each of the approaches separately and combined allow pursuit of more effective treatment strategies for this cancer. The methodology presented can also apply to other cancers, creating insights that current analytical methods could not find.

Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase fusion genes: A workshop report with focus on novel entities and a literature review including paediatric cases.

Myeloid/lymphoid neoplasms with eosinophilia (M/LN-eo) and tyrosine kinase (TK) gene fusions are a rare group of haematopoietic neoplasms with a broad range of clinical and morphological presentations. Paediatric cases have increasingly been recognised. Importantly, not all appear as a chronic myeloid neoplasm and eosinophilia is not always present. In addition, standard cytogenetic and molecular methods may not be sufficient to diagnose M/LN-eo due tocytogenetically cryptic aberrations. Therefore, additional evaluation with fluorescence in-situ hybridisation and other molecular genetic techniques (array-based comparative genomic hybridisation, RNA sequencing) are recommended for the identification of specific TK gene fusions. M/LN-eo with JAK2 and FLT3-rearrangements and ETV6::ABL1 fusion were recently added as a formal member to this category in the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In addition, other less common defined genetic alterations involving TK genes have been described. This study is an update on M/LN-eo with TK gene fusions with focus on novel entities, as illustrated by cases submitted to the Bone Marrow Workshop, organised by the European Bone Marrow Working Group (EBMWG) within the frame of the 21st European Association for Haematopathology congress (EAHP-SH) in Florence 2022. A literature review was performed including paediatric cases of M/LN-eo with TK gene fusions.

Enzyme-free dual amplification biosensor based on functional nucleic acid and CDs/CoOOH for detection of leukemia fusion gene

Acute promyelocytic leukemia (APL) is an acute myeloid leukemia (AML) with a specific fusion gene target, PML/RARα fusion gene (PML/RARα), which is formed by the translocation of chromosomes 15 and 17. Detection of PML/RARα is the most reliable parameter for the diagnosis, treatment adjustment, efficacy evaluation, prognosis analysis and relapse prediction of APL. In this study, a novel biosensor was constructed for rapid enzyme-free detection of PML/RARα using DNAzyme and carbon dots/cobalt oxhydroxide nanosheet complexs (CDs/CoOOH). In the detection system, the separated DNAzymes could specifically recognize and bind together by the PML/RARα to form a complete DNAzyme for shearing hairpin probe (HP), then generated trigger, which was the first signal amplification. Then, trigger could hybridize with the capture probe (CP) anchored to streptavidin (SA) modified microplate as well as fluorescence quenching signal probe (SP@CDs/CoOOH). Finally, ascorbic acid (AA) was added to decompose CoOOH and the fluorescence of CDs was released, which was the second signal amplification. Through the dual signal amplification of DNAzyme and CDs/CoOOH, PML/RARα could be detected quickly and sensitively, which overcame the limitation of protein enzyme in traditional fluorescence methods, showing potential clinical application value in the diagnosis and treatment of leukemia.

NKX3.1 immunohistochemistry and methylome profiling in mesenchymal chondrosarcoma: additional diagnostic value for a well-defined disease?

Mesenchymal chondrosarcoma (MCS) is a rare and highly aggressive tumour of soft tissue and bone that is defined by an underlying and highly specific fusion transcript involving HEY1 and NCOA2. Histologically, the tumours show a biphasic appearance consisting of an undifferentiated blue and round cell component as well as islands of highly differentiated cartilage. Particularly in core needle biopsies, the chondromatous component can be missed and the non-specific morphology and immunophenotype of the round cell component can cause diagnostic challenges. We applied NKX3.1 immunohistochemistry which was recently reported as a highly specific marker as well as methylome and copy number profiling to a set of 45 well characterised MCS cases to evaluate their potential diagnostic value. Methylome profiling revealed a highly distinct cluster for MCS. Notably, the findings were reproducible also when analysing the round cell and cartilaginous component separately. Furthermore, four outliers were identified by methylome profiling for which the diagnosis had to be revised. NKX3.1 immunohistochemistry showed positivity in 36% of tumours, the majority of which was rather focal and weak. Taken together, NKX3.1 expression showed a low sensitivity but a high specificity in our analysis. Methylome profiling on the other hand represents a sensitive, specific and reliable tool to support the diagnosis of MCS, particularly if only the round cell component is obtained in a biopsy and the diagnosis is not suspected. Furthermore, it can aid in confirming the diagnosis in case RNA sequencing for the HEY1::NCOA2 fusion transcript is not available.

Transcriptomic profiling and genomic rearrangement landscape of Nigerian prostate cancer.

Men of African ancestry have disproportionately high incidence rates of prostate cancer (PCa) and have high mortality rates. While there is evidence for a higher genetic predisposition for incidence of PCa in men of African ancestry compared to men of European ancestry, there have been few transcriptomic studies on PCa in men of African ancestry in the African continent. We performed transcriptomic profiling and fusion analysis on bulk RNA sequencing (RNA-seq) samples from 24 Nigerian PCa patients to investigate the transcriptomic and genomic rearrangement landscape of PCa in Nigerian men. Bulk RNA-seq was performed on 24 formalin-fixed paraffin-embeded (FFPE) prostatectomy specimens of Nigerian men. Transcriptomic analysis was performed on 11 high-quality samples. Arriba Fusion and STAR Fusion were used for fusion detection. 4/11 (36%) of the samples harbored an erythroblast transformation-specific (ETS)fusion event; 1/11 (9%) had a TMPRSS2-ERG fusion; 2/11 had a TMPRSS2-ETV5 fusion, and 1/11 had a SLC45A3-SKIL fusion. Hierarchical clustering of normalized and mean-centered gene expression showed clustering of fusion positive samples. Furthermore, we developed gene set signatures for Nigerian PCa based on fusion events. By projecting the cancer genome atlas prostate adenocarcinoma(TCGA-PRAD) bulk RNA-seq data set onto the transcriptional space defined by these signatures derived from Nigerian PCa patients, we identified a positive correlation between the Nigerian fusion signature and fusion positive samples in the TCGA-PRAD data set. Less frequent ETS fusion events other than TMPRSS2-ERG such as TMPRSS2-ETV5 and non-ETS fusion events such as SLC45A3-SKIL may be more common in PCa in Nigerian men. This study provides useful working transcriptomic signatures that characterize oncogenic states representative of specific gene fusion events in PCa from Nigerian men.

Correlation NKX2.2 IHC and EWSR1 break-apart FISH in the diagnosis of Ewing sarcoma: Can combined NKX2.2 and CD99 immunoexpression obviate or minimize the need of FISH testing? First assessment study from Indian tertiary cancer care center.

Ewing sarcoma (ES) are malignant small round cell tumors (MSRCT) characterized by rearrangements of EWSR1 gene. Although gold standard for diagnosis is detection of specific fusion genes by molecular testing, these ancillary tests are costly and only available in limited number of settings. There is a persuasive evidence for reliability of NKX2.2 immunohistochemistry (IHC) as a surrogate marker for EWSR1 gene rearrangement in ES. The aim of this study is to correlate the NKX2.2 immuno-expression with genetically confirmed ES cases and also to assess the reliability and accuracy of NKX2.2 along with combined positivity of NXX2.2 and CD99 in diagnosing ES and differentiating it from other relevant histological mimics. The present study is a retrospective study conducted over a period of 6-year duration in a tertiary cancer care center. We evaluated NKX2.2 immunoexpression in 35 genetically confirmed cases of ES and also in pertaining differential entities (n = 58) of ES including rhabdomyosarcoma (n = 20), lymphoblastic lymphoma (n = 14), Wilms tumor (n = 10), poorly differentiated synovial sarcoma (n = 4), small-cell osteosarcoma (n = 4), neuroblastoma (n = 5), and mesenchymal chondrosarcoma (n = 1). CD99 was performed in the category of MSRCTs showing NKX2.2 positivity to evaluate combined specificity for the diagnosis of ES. Of the 35 genetically confirmed cases of ES, 29 cases (83%) showed NKX2.2-positive expression (83% sensitivity). Compared to ES, NKX2.2 was positive in only 05% cases (3/58 cases) of non-ES MSRCT. Only two of five cases of neuroblastomas and one case of mesenchymal chondrosarcoma showed NKX2.2 positivity. CD99 positivity was seen in 100% of ES and in the single case of mesenchymal chondrosarcoma. All five cases (100%) of neuroblastoma were negative for CD99. The presented study, which is the first from an Indian oncology center, showed NKX2.2 IHC is quite reliable in diagnosis of ES in the right clinicopathological context. With remarkable sensitivity and specificity of NKX2.2 IHC for diagnosis of ES, we propose that combined positivity of CD99 and NKX2.2 IHC can obviate or minimize the need of EWSR1 gene rearrangement molecular testing for diagnosis of ES.

Epigenetic Features in Uterine Leiomyosarcoma and Endometrial Stromal Sarcomas: An Overview of the Literature.

There is a consensus that epigenetic alterations play a key role in cancer initiation and its biology. Studies evaluating the modification in the DNA methylation and chromatin remodeling patterns, as well as gene regulation profile by non-coding RNAs (ncRNAs) have led to the development of novel therapeutic approaches to treat several tumor types. Indeed, despite clinical and translational challenges, combinatorial therapies employing agents targeting epigenetic modifications with conventional approaches have shown encouraging results. However, for rare neoplasia such as uterine leiomyosarcomas (LMS) and endometrial stromal sarcomas (ESS), treatment options are still limited. LMS has high chromosomal instability and molecular derangements, while ESS can present a specific gene fusion signature. Although they are the most frequent types of “pure” uterine sarcomas, these tumors are difficult to diagnose, have high rates of recurrence, and frequently develop resistance to current treatment options. The challenges involving the management of these tumors arise from the fact that the molecular mechanisms governing their progression have not been entirely elucidated. Hence, to fill this gap and highlight the importance of ongoing and future studies, we have cross-referenced the literature on uterine LMS and ESS and compiled the most relevant epigenetic studies, published between 2009 and 2022.

Prevalence of salivary gland neoplasms in the head and neck in educational hospitals in Cairo Governorate

Background: Salivary gland neoplasms are morphologically diverse neoplasms with variable histology, clinical behavior, and tumor grade. Moreover, specific gene translocations and fusions are associated with some types of SGNs. Aim: To evaluate the prevalence of salivary gland neoplasms diagnosed in Cairo's educational hospitals and to compare the results with findings in the literature. Materials and Methods: Data of salivary gland neoplasms diagnosed between 2010 and 2019 were collected from the files of the Cairo's educational hospitals. Results: Salivary gland neoplasms in the present study constituted 2.4% of all the 9609 registered oral and maxillofacial biopsies. A total of 231 cases of SGNs were collected and reviewed. Of these, (61.1%) were benign and (38.9%) were malignant. Minor salivary glands (51.94%) were more involved than major ones (45.02%). Pleomorphic adenoma was the most frequent type of benign SGNs (68.8%) while Mucoepidermoid carcinoma was the most frequent type of malignant SGNs (46.7%). The mean age of SGNs was 41.14 ±15.43 years with a slight male predilection. Conclusion: In this study we observed a marked geographic variation in the relative frequency of various salivary gland neoplasms in Cairo government.

Abstract 2210: The study of age and race genetic signatures of prostate cancer with formalin fixed paraffin embedded (FFPE) samples

Abstract Objectives: Diagnosis with prostate cancer (PCa) at younger age is a serious challenge in Military Health System. PCa onset at younger age is more likely to be aggressive in African American (AA) population. Also, application of formalin fixed paraffin embedded (FFPE) tissue in RNA based study was significantly hindered due to poor quality/quantity of RNA in archived pathology slides. This study is aimed to examine age/race associated gene signatures in military cohort with high representation of AA and younger population in FFPE samples for potential genetic mechanisms of health disparities and broaden tissue sample availability. Methods: A cohort of 41 Caucasian American (CA) and 20 AA non-familial PCa patients from the biospecimen bank of CPDR, WRNMMC were used. Specimens donated by radical prostatectomy patients who provided written consent and protocols approved by Institutional Review Boards. Total RNA was extracted from tumor and the adjacent normal epithelium of whole-mount FFPE tissue of matched specimens. Differential gene expression, in tumor versus normal tissues, between younger and older AA and CA patients were analyzed by NanoString using a customized CodeSet of 151 probes. The panel designed to detect 135 target transcripts, compiled from 34 genes implicated/associated with PCa progression, 27 PCa specific gene fusions, 25 cancer-associated genes, and 5 genes encoding ETS-family of transcription factors. The 27 over-expressed genes and 17 under-expressed genes in PCa were included as comparison to matched, benign epithelium. Additionally, 5 prostate stroma or epithelium specific genes were selected as control and 11 housekeeping genes were included for biological normalization. Results: The differentially expressed genes related to tumor-normal differences between AA older (66-73 years) and younger (42-58 years) as well as CA older and younger PCa patients with moderate Gleason score (3+3 and 3+4) sum were identified. After controlling for false discovery rates, panel of nine genes (ANXA2, C-MYC, VEGFR1, ERG, NPY, PSMA/FOLH1, TWIST1, MAOA, MYCN) uniquely associated with age/race were identified. Tumor vs normal ratios of ANXA2 and C-MYC expression in prostate tumors of older and younger patients were significantly enhanced. We found a clear association of VEGFR1 gene expression with CA young and c-MYC gene with AA young PCa. Conclusions: Using age/race as endpoint, we identified ANXA2, c-MYC and VEGFR1 as age and race associated PCa gene. Our findings highlight distinct racial and age-related differences and addresses the clinical utility of available genetic tests across old and young AA and CA men, which needs to be further validated in lager cohort. Further, our study also highlighted the utilization of FFPE tissue for NanoString assay and subsequent genetic signature analyses. Citation Format: Shashwat Sharad, Darryl Nousome, Gregory T. Chesnut, Hua Li. The study of age and race genetic signatures of prostate cancer with formalin fixed paraffin embedded (FFPE) samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2210.

Use of clinical RNA-sequencing in the detection of actionable fusions compared to DNA-sequencing alone.

3077 Background: While targeted DNA-seq can detect clinically actionable fusions in tumor tissue samples, technical and analytical challenges may give rise to false negatives. RNA-based, whole-exome sequencing provides a complementary method for fusion detection, and may improve the identification of actionable variants. In this study, we quantify this benefit using a large, real-world clinical dataset to assess actionable fusions detected from RNA in conjunction with DNA profiling. Methods: Using the Tempus Research Database, we retrospectively analyzed a de-identified dataset of ̃80K samples (77.4K patients) profiled with the Tempus xT assay (both DNA-seq with fusion detection in 21 genes and whole exome capture RNA-seq). Only patients that had successful RNA- and DNA-seq were included. Fusions were detected using the Tempus bioinformatic and clinical workflow. Candidate fusions were filtered based on read support thresholds, fusion annotation ( i.e., breakpoints, reading frame, conserved domains), and manual review. OncoKB was used to select fusion alterations in levels 1 and 2 and to identify those indication-matched to targeted therapies. Results: We identified 2118 level 1 and 2 fusion events across 1945 patients across 20 different cancer types. Most fusions were observed in non-small cell lung cancer (NSCLC) (25%) and biliary cancer (9%) samples. Of the 2118 fusion events, 29.1% (616) were detected only through RNA-seq while 4.8% (101) of the events were identifiable only through DNA-seq. Notably, 69.4% of fusions in low-grade glioma and 58.2% in sarcomas were detected only by RNA-seq. When evaluating specific gene fusion events, RNA-seq consistently improved the detection of fusions compared to DNA-seq alone (Table) across all cancer types. A total of 1106 fusions were classified as targetable by OncoKB indication-matched therapies with 19% (214) of these identifiable through RNA-seq alone, 5% (54) by DNA-seq alone, and 76% (838) identifiable through RNA- and DNA-seq. Overall, fusions identified through RNA-seq alone led to a 24% increase in the number of patients who were eligible to receive matched therapies (214 / 892). This included imatinib for patients with CML/BLCL (69.8%), crizotinib for NSCLC (40.3%) and entrectinib for NTRK and ROS1 fusions (32.5%). Conclusions: The addition of RNA-seq to DNA-seq significantly increased the detection of fusion events and ability to match patients to targeted therapies. Results support consideration of combined RNA-DNA-seq for standard-of-care fusion calling. [Table: see text]

Clinical features and prognosis of childhood B-lineage acute lymphoblastic leukemia expressing the PRAME gene

To study the clinical and prognostic significance of the preferentially expressed antigen of melanoma (PRAME) gene in the absence of specific fusion gene expression in children with B-lineage acute lymphoblastic leukemia (B-ALL). A total of 167 children newly diagnosed with B-ALL were enrolled, among whom 70 were positive for the PRAME gene and 97 were negative. None of the children were positive for MLL-r, BCR/ABL, E2A/PBX1, or ETV6/RUNX1. The PRAME positive and negative groups were analyzed in terms of clinical features, prognosis, and related prognostic factors. Compared with the PRAME negative group, the PRAME positive group had a significantly higher proportion of children with the liver extending >6 cm below the costal margin (P<0.05). There was a significant reduction in the PRAME copy number after induction chemotherapy (P<0.05). In the minimal residual disease (MRD) positive group after induction chemotherapy, the PRAME copy number was not correlated with the MRD level (P>0.05). In the MRD negative group, there was also no correlation between them (P>0.05). The PRAME positive group had a significantly higher 4-year event-free survival rate than the PRAME negative group (87.5%±4.6% vs 73.5%±4.6%, P<0.05), while there was no significant difference between the two groups in the 4-year overall survival rate (88.0%±4.4% vs 85.3%±3.8%, P>0.05). The Cox proportional-hazards regression model analysis showed that positive PRAME expression was a protective factor for event-free survival rate in children with B-ALL (P<0.05). Although the PRAME gene cannot be monitored as MRD, overexpression of PRAME suggests a good prognosis in B-ALL.

Leveraging artificial intelligence to predict ERG gene fusion status in prostate cancer.

BackgroundTMPRSS2-ERG gene rearrangement, the most common E26 transformation specific (ETS) gene fusion within prostate cancer, is known to contribute to the pathogenesis of this disease and carries diagnostic annotations for prostate cancer patients clinically. The ERG rearrangement status in prostatic adenocarcinoma currently cannot be reliably identified from histologic features on H&E-stained slides alone and hence requires ancillary studies such as immunohistochemistry (IHC), fluorescent in situ hybridization (FISH) or next generation sequencing (NGS) for identification.MethodsObjectiveWe accordingly sought to develop a deep learning-based algorithm to identify ERG rearrangement status in prostatic adenocarcinoma based on digitized slides of H&E morphology alone.DesignSetting, and Participants: Whole slide images from 392 in-house and TCGA cases were employed and annotated using QuPath. Image patches of 224 × 224 pixel were exported at 10 ×, 20 ×, and 40 × for input into a deep learning model based on MobileNetV2 convolutional neural network architecture pre-trained on ImageNet. A separate model was trained for each magnification. Training and test datasets consisted of 261 cases and 131 cases, respectively. The output of the model included a prediction of ERG-positive (ERG rearranged) or ERG-negative (ERG not rearranged) status for each input patch.Outcome measurements and statistical analysis: Various accuracy measurements including area under the curve (AUC) of the receiver operating characteristic (ROC) curves were used to evaluate the deep learning model.Results and LimitationsAll models showed similar ROC curves with AUC results ranging between 0.82 and 0.85. The sensitivity and specificity of these models were 75.0% and 83.1% (20 × model), respectively.ConclusionsA deep learning-based model can successfully predict ERG rearrangement status in the majority of prostatic adenocarcinomas utilizing only H&E-stained digital slides. Such an artificial intelligence-based model can eliminate the need for using extra tumor tissue to perform ancillary studies in order to assess for ERG gene rearrangement in prostatic adenocarcinoma.