NTRK1 Research Articles

Evolving Patient-Centred Therapies for Metastatic NSCLC

The metastatic non-small cell lung cancer (mNSCLC) treatment landscape has vastly expanded over the past two decades as a result of advancements in biomarker testing. However, unmet needs remain both in terms of treatment options for some patient groups, and patient support throughout the treatment journey. In this symposium, Jarushka Naidoo, Consultant Medical Oncologist, Beaumont RCSI Cancer Centre, Dublin, Ireland; Terri Conneran, KRAS Kickers, Charlotte, North Carolina, USA; Luis Paz-Ares, Chair of the Medical Oncology Department, Hospital Universitario 12 de Octubre, Madrid, Spain; and Alexander Drilon, Chief of Early Drug Development and Thoracic Oncology, Memorial Sloan Kettering Cancer Center, New York, USA, focused on patient-centric approaches to mNSCLC treatment, starting with a patient and patient advocacy group perspective on what patients want from their care team during their treatment journey. The panel also discussed both immuno-oncology (I-O) monotherapy and combination therapy, including dual I-O therapies for patients with programmed death-ligand 1 (PD-L1) tumour expression <1%, as well as the treatment landscape for KRASG12C-mutated mNSCLC, and ongoing trials of KRAS-targeted agents. In addition, the latest data on tyrosine kinase inhibitors (TKI) for patients with alterations in ROS1 and NTRK genes were discussed, focusing on next-generation TKIs. Finally, the panel discussed patient cases, taking into account specific considerations and how to best approach treatment decisions.

Living without pain: A 10-year study of congenital insensitivity to pain with anhidrosis.

Congenital Insensitivity to Pain with Anhidrosis (CIPA) is a rare hereditary neuropathy caused by NTRK1 gene mutations, predisposing patients to recurrent infections and chronic wounds. Long-term studies on microbial and clinical outcomes in CIPA are limited. This study presents analysis of infection patterns, antibiotic resistance, and clinical outcomes in CIPA patients. A comprehensive ten-year retrospective cohort study was conducted at Soroka University Medical Center, Beer Sheva, Israel, from January 2014 to January 2023. Electronic medical records were reviewed to identify 63 CIPA patients, all were of consanguineous Bedouin families. Data collection included demographic details, clinical presentations, genetic analysis, documentation of infections, wound sites, hospital duration, and surgical interventions. Staphylococcus aureus, notably methicillin-resistant, dominated, with Gram-negative bacteria common in lower limbs. The study noted reduced extended-spectrum beta-lactamase bacteria and linked demographic factors to infection traits, antibiotic resistance, and surgical needs. This study provides valuable insights into the clinical and microbial patterns of CIPA, highlighting dynamic shifts in microbial compositions and antibiotic resistance profiles over time. Staphylococcus aureus, and Gram-negative bacteria particularly in lower limb infections, pose significant challenges in patient management. The findings underscore the importance of tailored approaches to address evolving microbial profiles and optimize patient care in CIPA. Key Message: This is the largest cohort study on CIPA to date, highlighting the dominance of Staphylococcus aureus, including methicillin-resistant strains, and significant Gram-negative bacterial infections in lower limbs. Contribution to Literature: It draws parallels between infection dynamics in CIPA and diabetic foot ulcers, emphasizing similar challenges due to neuropathy and ischemia, enhancing understanding of infection susceptibility and management in neuropathic conditions. The findings inform clinical practices by detailing infection and resistance patterns, supporting the development of targeted treatment strategies to improve outcomes for CIPA and similar conditions.

Rare Presentation of Extraskeletal Osteosarcoma Mimicking Phyllodes Tumor

Abstract Introduction/Objective A 57-year-old female presented with a palpable mass in the left breast, measuring up to 9 cm by ultrasound. core needle biopsy identified an atypical spindle cell lesion. The differential diagnosis included a metaplastic carcinoma, borderline phyllodes tumor, malignant phyllodes tumor with potential sarcomatous transformation. Methods/Case Report Histological examination of the tumor was performed, and immunohistochemical stains were conducted to characterize the lesion. Further consultation with a specialized pathologist at the University of Michigan was sought to confirm the diagnosis. Molecular analysis was performed to assess for specific genetic alterations and expression patterns. The histological examination revealed a proliferation of atypical spindle cells forming a fascicular and storiform pattern, with numerous large, pleomorphic, multinucleated tumor cells and a high mitotic rate. Immunohistochemical stains showed strong positivity for CD10 and vimentin, with focal weak expression for desmin, and negativity for a broad panel of cytokeratins and other markers. Consultation with Dr. Abbott at the University of Michigan supported the diagnosis of extraskeletal osteosarcoma. Molecular analysis revealed PD-L1 expression and absence of NTRK gene fusions. FISH analysis showed suggestive alterations including loss of BRAF gene, loss of MYC, and suggestive gains or polysomy of PTEN gene. Results (if a Case Study enter NA) NA Conclusion The case represents a rare presentation of extraskeletal osteosarcoma in the breast, with distinctive histological and immunohistochemical features. The comprehensive workup including histology, immunohistochemistry, and molecular analysis aids in accurate diagnosis and potential therapeutic implications. Further research may elucidate the underlying mechanisms and treatment options for this uncommon malignancy.

NTRK Gene Expression Analysis in Oral Squamous Cell Carcinoma Mexican Population.

Oral cancer holds the sixth position in malignancies worldwide; 90% correspond to oral squamous cell carcinoma (OSCC). Diverse reports suggest that NTRK genes and their receptors are key oncogenesis regulators to tumor progression in human cancers. Objective: To analyze the NTRK and Trk expression and their association with clinicopathological features of OSCC in Mexican patients' samples. Material and Methods: We analyzed 95 OSCC cases of pan-trk immunoexpression through a software-assisted method. Gene expression was analyzed by RT-qPCR employing the ΔΔCT method. Kruskal-Wallis and Spearman's correlation tests were performed. Results: Our mean age was 62.4 (±16.9) years. A total of 37 cases were tumors in the lateral border of the tongue. Age was significantly associated with the anatomical site. 42% (40 of 95) cases were pan-trk positive. A total of 21 cases showed intense immunoexpression predominantly in poorly differentiated OSCC, with a significant correlation between immunoexpression and age and gender. Gene expression showed that poorly differentiated cases exhibited higher NTRK2 expression, while well-differentiated cases demonstrated NTRK3 significantly higher expression. Conclusions: Our results suggest that NTRK family expression is present in OSCC, with differential expression related to differentiation degree. Additional information about their activation or mutational status could reinforce their potential as a possible primary or adjuvant treatment target.

Updated EANO guideline on rational molecular testing of gliomas, glioneuronal, and neuronal tumors in adults for targeted therapy selection - Update 1.

The standard of care for adult patients with gliomas, glioneuronal and neuronal tumors consists of combinations of surgery, radiotherapy, and chemotherapy. For many systemic cancers, targeted treatments are a major part of the standard treatment, however, the predictive significance of most of the targets for treatment in systemic cancer are less well established in central nervous system (CNS) tumors . In 2023 the EANO Guideline Committee presented evidence based recommendations for rational testing of molecular targets for targeted treatments. From all targets reviewed, only testing for BRAF V600E mutations was of proven clinical benefit; despite regulatory approvals for tumor agnostic treatment of NTRK gene fusions and high Tumor Mutational Burden (TMB) for patients with adult brain tumors, the evidence of clinical benefit for patients was still limited . This guideline has a modular structure, allowing regular updating of individual sections and adding new ones. The present version (Update 1) presents a review of the rationale of testing for PTEN, H3F3A, MTAP, RET and IDH, and presents an update of the text on TMB high and mismatch repair deficiency. It also presents an overview of therapeutic yield of routine next generation sequencing for mutations and fusion detection. The supplement accompanying this version contains the in depth review of all targets, whereas in the main manuscript the final recommendations of the revised and new targets are presented. Updates will be made on a regular basis.

8788 Implications of NTRK gene fusion in Papillary thyroid cancer

Abstract Disclosure: W. Medina-Torres: None. L. El Musa Penna: None. J. Segarra-Villafane: None. L.R. Sepulveda-Garcia: None. Z. Maisonet -Feliciano: None. I.C. Arroyo: None. M. Ramirez: None. M. Alvarado: None. L.A. Gonzalez-Rodriguez: None. V.J. Carlo: None. Thyroid cancer (TC) is the most common endocrine cancer. Papillary thyroid carcinoma (PTC) is the predominant contributor of this occurrence, comprising approximately 80% of all thyroid carcinomas. PTC has a good prognosis with a 5-year survival rate of more than 90% after resection. Nonetheless, factors such as tumor size, multifocality, nodal and distant metastases, characterize more aggressive cases including tall cell variant, columnar cell variant, and hobnail variant Aside from staging parameters, PTC behavior is mostly determined by morphologic variant. This is the case of 31 y/o female without known past medical history who was evaluated at endocrinology clinic due to a fine needle thyroid aspiration (FNA) positive for PTC, tall cell variant. Total thyroidectomy with central compartment dissection was performed. Pathology report presented a main tumoral mass of 3 cm but permeating multinodular pattern involving the entire gland with focal extrathyroidal extension, positive margins and six level VI positive lymph nodes. As per report, the tumor presented both papillary and follicular patterns of growth and other findings including oncocytic change, foci of clear cell change, low mitotic rate, and most notably "reverse polarization”. This pattern has the pathological features suggestive of the novel NTRK gene fusion mutation. The patient was treated with radioactive iodine (RAI) and one year post treatment there was evidence of elevated Thyroglobulin level at 904 ng/mLand thyroglobulin Ab at 2.48 IU/mL. A WBS +SPECT was done resulting in small uptake at left posterior thyroid bed and pulmonary intake. A chest CT revealed multiple bilateral sub centimeter nodules. Based on this result, a second course of RAI was given. Follow up neck ultrasound and chest CT presented persistent left level VI lymph nodes, increased amount of bilateral sub-centimeter pulmonary nodules and new thoracic(T11) lesion. FNA of left neck lymph nodes were positive for metastatic PTC for which left neck dissection was performed. Evaluation for actionable somatic mutations was requested based on resistance behavior, remarkable for TRIM33-NTRK1 chromosomal rearrangement. Patient was evaluated by Oncology service who started Larotrectinib treatment since it was approved for NTRK driven malignancies. Six-month post therapy patient achieved clinical and biochemical improvement. In the thyroid, NTRK-driven malignancies are rare and aggressive but treatable, in the evolving genomic era. As reviewed in the literature, NTRK fusion-positive TC exhibits distinctive clinicopathological features that could aid in identifying potential patients. Thus, in such patients who have PTC with non-classic pathologic patterns, specific molecular profile of the main tumor may have significant prognostic value that must be integrated into stratification system in order to provide target therapy on time. Presentation: 6/3/2024

Atypical Presentation of Congenital Insensitivity to Pain With Anhidrosis Leading to Diagnostic Odyssey.

Congenital insensitivity to pain with anhidrosis (CIPA) (OMIM 256800) is a rare autosomal-recessive condition, also known as hereditary sensory and autonomic neuropathy type IV (HSAN-IV). The most commonly reported features include anhidrosis, intellectual disability, self-mutilation, febrile episodes, impaired temperature perception, recurrent infections and/or autonomic nervous system impairment. Major joint destruction and joint deformity known as Charcot (neuropathic) joints are also seen in CIPA patients attributed to insensitivity to joint pain. We present a case of a 46-year-old female affected with CIPA with a known NTRK1 variant and previously unidentified variant. Minigene reporter constructs were generated encompassing the exon 8 to exon 13 of the NTRK1 gene using the reference sequence and one harboring c.1483 + 5G > A variant identified in our proband. Minigene constructs were transfected into HEK293T cells, and the transcript was analysed for splicing to evaluate the effect of this variant in splicing. The patient (46-year-old female) exhibited right ankle joint deformity around 5 years of age. Patient also experienced lumbar compression and knee damage in adulthood. She had undergone a significant number of evaluations without clear diagnosis. Her presentation lacked many of the common clinical presentations of CIPA, and therefore, the focus of her evaluation was directed towards her unexplained joint deformities. Exome sequencing revealed a known pathogenic variant in NTRK1 (c.851-33T > A:p.? [Intron 7]) and a novel NTRK1 variant (c.1483 + 5G > A:p.? [Intron 11]), which was later re-classified as likely pathogenic. The patient was started on a biologic disease-modifying anti-rheumatic medication (bDMARD) due to a possible inflammatory etiology of her joint deformity. Molecular diagnosis allowed for modification of her treatment and surveillance strategies. Our minigene splicing assay demonstrated that the presence of the c.1483 + 5G > A variant has a negative effect on splicing, supporting the pathogenicity of this novel variant.

Rare Oncogenic Fusions in Pediatric Central Nervous System Tumors: A Case Series and Literature Review

Background and Objectives: Central Nervous System (CNS) pediatric tumors represent the most common solid tumors in children with a wide variability in terms of survival and therapeutic response. By contrast to their adult counterpart, the mutational landscape of pediatric CNS tumors is characterized by oncogenic fusions rather than multiple mutated genes. CNS pediatric tumors associated with oncogenic fusions represent a complex landscape of tumors with wide radiological, morphological and clinical heterogeneity. In the fifth CNS WHO classification, there are few pediatric CNS tumors for which diagnosis is based on a single oncogenic fusion. This work aims to provide an overview of the impact of rare oncogenic fusions (NTRK, ROS, ALK, MET, FGFR, RAF, MN1, BCOR and CIC genes) on pathogenesis, histological phenotype, diagnostics and theranostics in pediatric CNS tumors. We report four cases of pediatric CNS tumors associated with NTRK (n = 2), ROS (n = 1) and FGFR3 (n = 1) oncogenic fusion genes as a proof of concept. Cases presentation and literature review: The literature review and the cohort that we described here underline that most of these rare oncogenic fusions are not specific to a single morpho-molecular entity. Even within tumors harboring the same oncogenic fusions, a wide range of morphological, molecular and epigenetic entities can be observed. Conclusions: These findings highlight the need for caution when applying the fifth CNS WHO classification, as the vast majority of these fusions are not yet incorporated in the diagnosis, including grade evaluation and DNA methylation classification.

Association of NTRK2 gene with suicidality: a meta-analysis

Background Previous studies have shown that genes in brain development pathways may have important roles in affecting risk of suicidal behaviors, with our previous meta-analysis supporting a role of the brain-derived neurotrophic factor (BDNF) gene. NTRK2 is a gene that encodes the neurotrophic receptor tyrosine kinase 2, which is a receptor for BDNF. In the current study, we aim to examine the potential association between NTRK2 single nucleotide polymorphism (SNPs) and suicidal ideation/behaviors. Methods We first conducted a literature search using keywords like ‘NTRK2’, ‘TRKB’, and ‘suicid*’ to identify papers on NTRK2 SNPs and suicidal ideation/behaviors. In addition, we have individual-level genotype data for all the identified SNPs in literature search. We used the R meta package to perform meta-analyses on both the genotype count and the allele count data. Moreover, we performed meta-analyses on specific haplotypes within each haplotype block. Main results Following our literature search and meta-analyses on 20 NTRK2 SNPs across up to 8467 samples, we found three SNPs, rs10868235 [N = 5,318, odds ratio (OR) = 1.34, P = 0.02], rs1867283 (N = 5,134, OR = 0.73, P = 0.04), and rs1147198 (N = 5,132, OR = 1.36, P = 0.03) to be nominally associated with suicidal attempts. Those three findings, however, did not survive multiple-testing corrections. Also, none of the haplotype blocks showed significant involvement in suicidality. Conclusion Our results suggest that the NTRK2 gene may not have a major role in suicidality. Future efforts, however, should explore gene–gene interaction and pathway analyses.

Current Landscape of NTRK Inhibition for Pediatric CNS Tumors.

Over the last decade, as molecular platforms have permitted the characterization of the genomic landscape of pediatric central nervous system (CNS) tumors, pediatric neuro-oncology has dramatically transformed. NTRK fusions are oncogenic driver alterations that have been found in a multitude of tumor types, including pediatric CNS tumors. In recent years, NTRK inhibitors have emerged as a promising class of targeted therapies for pediatric CNS tumors with NTRK gene fusions. The use of larotrectinib and entrectinib in the relapsed setting for pediatric CNS tumors has resulted in rapid and robust responses in an important fraction of patients. These agents are well tolerated, although close to 20% of patients have spontaneous bone fractures. Given the existing data for patients with relapsed disease, clinical trials using NTRK inhibitors in the upfront setting is the next natural progression of efficacy testing and many are currently underway. There are still several challenges that need to be addressed to optimize the use of NTRK inhibitors and identify the patients with NTRK fusion-positive CNS tumors who are most likely to benefit from them. As these agents are more broadly used, resistance will become a more pervasive issue and strategies will need to be determined for this scenario. This article summarizes the current status of NTRK inhibitors for pediatric CNS tumors and discusses the opportunities and challenges of their expanding use in the future.

Secretory Carcinoma of the Breast: Radiologic-Pathologic Correlation.

Secretory carcinoma is a rare, low-grade, special histological type of invasive breast carcinoma. Although it is the most common primary breast cancer in the pediatric population, most cases are diagnosed in adults, with a median age of 48 years (range 3 to 91 years). It most often presents as a painless and slowly growing palpable lump. Imaging findings are nonspecific. Secretory carcinomas have abundant periodic acid-Schiff positive intracytoplasmic and extracellular secretions on histopathology. Nearly all secretory carcinomas have mild to moderate nuclear pleomorphism with low mitotic activity. Over 80% (86/102) of secretory carcinomas display the translocation of t(12;15)(p13;q25), resulting in ETV6::NTRK3 gene fusion. Secretory carcinoma generally has an indolent course and has a better prognosis and overall survival than invasive breast carcinoma of no special type. A good prognosis is associated with age <20 years, tumor size <2 cm, and ≤3 axillary lymph node metastases. Metastases beyond the ipsilateral axillary lymph nodes are rare, with the most common sites involving the lung and liver. Except for the potential addition of targeted drug therapy for NTRK fusion-positive tumors, the treatment approach is otherwise similar to invasive breast carcinomas of similar receptor status.

Rapid molecular profiling utilising minimal quantities of endobronchial ultrasound-guided aspirates for the detection of Epidermal Growth Factor Receptor, KRAS, ALK, ROS1, RET, NTRK and MET gene alterations from patients with non-small-cell lung carcinomas on the Biocartis Idylla™ platform.

Comprehensive molecular analysis for patients with non-small-cell lung carcinoma (NSCLC) is essential for managing modern targeted therapies. This study sought to establish the feasibility of utilising real-time PCR to perform rapid and comprehensive profiling on minimal amounts of endobronchial ultrasound-guided (EBUS) aspirates as a fast, tissue-sparing route of predictive profiling. A volume of 500 μL of EBUS aspirate and fixative from patients with NSCLC was decanted, and 80 μL (<1% of total specimen received) was utilised for analysis. Biocartis Idylla™ cartridges for epidermal growth factor receptor (EGFR) mutations, KRAS mutations and a GeneFusion cartridge (ALK, ROS1, RET, NTRK1/2/3 rearrangements & MET 14 exon skipping) were analysed for each case to provide molecular data on the main clinically relevant targets as per UK guidelines. A total of 62 cases were included; all of which had successful DNA analysis (EGFR and KRAS cartridges). RNA analysis (GeneFusion cartridge) was successful for 42 of 51 (82%) with initial approach, with 11 of 11 (100%) achieving a successful result with modified protocol. In all, 23 KRAS mutations (37%), 5 EGFR mutations (8%) and 1 ROS fusion (2%) were identified. Average time from specimen receipt to molecular read-out was 5 h. Real-time PCR utilising the Idylla™ platform is rapid, utilises minimal amounts of tissue and provides accurate results. We propose this is a useful ancillary method to utilise alongside next-generation sequencing (NGS) in cases of urgent clinical requirement or EBUS aspirates with inadequate quantities of tissue for NGS.

Pediatric Fibromatosis Lacks the Internal Tandem Duplication of EGFR Seen in Congenital Mesoblastic Nephroma.

Classical and mixed congenital mesoblastic nephroma (CMN) are characterized by an internal tandem duplication (ITD) of the EGFR gene, in contrast to cellular CMN that usually harbors an ETV6::NTRK3 gene fusion. This same fusion occurs in infantile fibrosarcoma, and this tumor can be considered as the soft tissue equivalent of cellular CMN. A soft tissue equivalent of classic/mixed CMN remains undefined at the genetic level. Since classical CMN resembles fibromatosis of soft tissue histologically, we asked whether fibromatosis in children might show EGFR ITD. ITD was investigated using the polymerase chain reaction and primers for exons 18 and 25 of the EGFR gene. Seven of the eight cases of classical or mixed CMN were positive by this approach, but none of the five cellular CMNs. Of 11 cases of fibromatosis (six plantar, two digital, and three desmoid), none were positive for EGFR ITD. Within the limits of this small study, we conclude that pediatric fibromatosis is likely not characterized by EGFR ITD. There are isolated reports of pediatric soft tissue tumors that harbor EGFR ITD, but these have the appearance of infantile fibrosarcoma or mixed CMN rather than fibromatosis. We did not find any such cases, since all 14 cases of infantile fibrosarcoma in our study had an ETV6::NTRK3 fusion. The soft tissue tumors with EGFR ITD are not a morphologic match for the low-grade histology of classical CMN. Whether they have a similar favorable biology or behave more like fibrosarcoma with an ETV6::NTRK3 fusion or an alternative fusion involving other kinases remains to be determined.

NTRK gene alterations were enriched in hepatoid or enteroblastic differentiation type of gastric cancer

AimsCurrently, the clinicopathological characteristics of gastric cancer (GC) with oncogenic NTRK alterations are not well known. Although NTRK fusion has been identified as prevalent in DNA mismatch repair protein deficient...

Unveiling an anoikis-related risk model and the role of RAD9A in colon cancer

ObjectiveColorectal cancer (CRC), specifically colon adenocarcinoma, is the third most prevalent and the second most lethal form of cancer. Anoikis is found to be specialized form of programmed cell death (PCD), which plays a pivotal role in tumor progression. This study aimed to investigate the role of the anoikis related genes (ARGs) in colon cancer. MethodsConsensus unsupervised clustering, differential expression analysis, tumor mutational burden analysis, and analysis of immune cell infiltration were utilized in the study. For the analysis of RNA sequences and clinical data of COAD patients, data from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) were obtained. A prognostic scoring system for overall survival (OS) prediction was developed using Cox regression and LASSO regression analysis. Furthermore, loss-of-function assay was utilized to explore the role of RAD9A played in the progression of colon cancer. ResultsThe prognostic value of a risk score composed of NTRK2, EPHA2, RAD9A, CDC25C, and SNAI1 genes was significant. Furthermore, these findings suggested potential mechanisms that may influence prognosis, supporting the development of individualized treatment plans and management of patient outcomes. Further experiments confirmed that RAD9A could promote proliferation and metastasis of colon cancer cells. These effects may be achieved by affecting the phosphorylation of AKT. ConclusionDifferences in survival time and the tumor immune microenvironment (TIME) were observed between two gene clusters associated with ARGs. In addition, a prognostic risk model was established and confirmed as an independent risk factor. Furthermore, our data indicated that RAD9A promoted tumorigenicityby activating AKT in colon cancer.

Pyrazolo[1,5-a]pyrimidine as a Prominent Framework for Tropomyosin Receptor Kinase (Trk) Inhibitors-Synthetic Strategies and SAR Insights.

Tropomyosin receptor kinases (Trks) are transmembrane receptor tyrosine kinases named TrkA, TrkB, and TrkC and encoded by the NTRK1, NTRK2, and NTRK3 genes, respectively. These kinases have attracted significant attention and represent a promising therapeutic target for solid tumor treatment due to their vital role in cellular signaling pathways. First-generation TRK inhibitors, i.e., Larotrectinib sulfate and Entrectinib, received clinical approval in 2018 and 2019, respectively. However, the use of these inhibitors was significantly limited because of the development of resistance due to mutations. Fortunately, the second-generation Trk inhibitor Repotrectinib (TPX-0005) was approved by the FDA in November 2023, while Selitrectinib (Loxo-195) has provided an effective solution to this issue. Another macrocycle-based analog, along with many other TRK inhibitors, is currently in clinical trials. Two of the three marketed drugs for NTRK fusion cancers feature a pyrazolo[1,5-a] pyrimidine nucleus, prompting medicinal chemists to develop numerous novel pyrazolopyrimidine-based molecules to enhance clinical applications. This article focuses on a comprehensive review of chronological synthetic developments and the structure-activity relationships (SAR) of pyrazolo[1,5-a]pyrimidine derivatives as Trk inhibitors. This article will also provide comprehensive knowledge and future directions to the researchers working in the field of medicinal chemistry by facilitating the structural modification of pyrazolo [1,5-a]pyrimidine derivatives to synthesize more effective novel chemotherapeutics as TRK inhibitors.

Deciphering Trachinotus ovatus resistance to Streptococcus agalactiae:GWAS identification of key SNPs and candidate genes

The genetic basis of resistance in Trachinotus ovatus to Streptococcus agalactiae, a prevalent pathogen in warm-water fish, was explored in this study. T. ovatus, an economically significant marine fish, is widely distributed in tropical and subtropical oceans. This research involved the whole-genome resequencing of 200 T. ovatus individuals and a genome-wide association study (GWAS) to identify significant single nucleotide polymorphisms (SNPs) associated with resistance to S. agalactiae. Methods included infection experiments with S. agalactiae, quality control of DNA samples, high-throughput sequencing, SNP detection and quality control, analysis of population genetic structure, linkage disequilibrium (LD) analysis, GWAS, screening of candidate genes, and genotyping of significant SNPs. Results indicated a significant association of specific SNP loci with resistance in T. ovatus to S. agalactiae, notably SNP18597184 on chromosome LG9, associated with the NTRK3 and IFNK genes involved in neural development, survival, and immune response.

Seasonal variation of NGF in seminal plasma and expression of NGF and its cognate receptors NTRK1 and p75NTR in the sex organs of rams

Nerve growth factor (NGF) has long been known as the main ovulation-inducing factor in induced ovulation species, however, recent studies suggested the NGF role also in those with spontaneous ovulation. The first aim of this study was to evaluate the presence and gene expression of NGF and its cognate receptors, high-affinity neurotrophic tyrosine kinase 1 receptor (NTRK1) and low-affinity p75 nerve growth factor receptor (p75NTR), in the ram genital tract. Moreover, the annual trend of NGF seminal plasma values was investigated to evaluate the possible relationship between the NGF production variations and the ram reproductive seasonality. The presence and expression of the NGF/receptors system was evaluated in the testis, epididymis, vas deferens ampullae, seminal vesicles, prostate, and bulbourethral glands through immunohistochemistry and real-time PCR (qPCR), respectively. Genital tract samples were collected from 5 adult rams, regularly slaughtered at a local abattoir. Semen was collected during the whole year weekly, from 5 different adult rams, reared in a breeding facility, with an artificial vagina. NGF seminal plasma values were assessed through the ELISA method. NGF, NTRK1 and p75NTR immunoreactivity was detected in all male organs examined. NGF-positive immunostaining was observed in the spermatozoa of the germinal epithelium, in the epididymis and the cells of the secretory epithelium of annexed glands, NTRK1 receptor showed a localization pattern like that of NGF, whereas p75NTR immunopositivity was localized in the nerve fibers and ganglia. NGF gene transcript was highest (p < 0.01) in the seminal vesicles and lowest (p < 0.01) in the testis than in the other tissues. NTRK1 gene transcript was highest (p < 0.01) in the seminal vesicles and lowest (p < 0.05) in all the other tissues examined. Gene expression of p75NTR was highest (p < 0.01) in the seminal vesicles and lowest (p < 0.01) in the testis and bulbourethral glands. NGF seminal plasma concentration was greater from January to May (p < 0.01) than in the other months. This study highlighted that the NGF system was expressed in the tissues of all the different genital tracts examined, confirming the role of NGF in ram reproduction. Sheep are short-day breeders, with an anestrus that corresponds to the highest seminal plasma NGF levels, thus suggesting the intriguing idea that this factor could participate in an inhibitory mechanism of male reproductive activity, activated during the female anestrus.

Atypical cellular responses mediated by intracellular constitutive active TrkB (NTRK2) kinase domains and a solely intracellular NTRK2-fusion oncogene

Trk (NTRK) receptor and NTRK gene fusions are oncogenic drivers of a wide variety of tumors. Although Trk receptors are typically activated at the cell surface, signaling of constitutive active Trk and diverse intracellular NTRK fusion oncogenes is barely investigated. Here, we show that a high intracellular abundance is sufficient for neurotrophin-independent, constitutive activation of TrkB kinase domains. In HEK293 cells, constitutive active TrkB kinase and an intracellular NTRK2-fusion oncogene (SQSTM1-NTRK2) reduced actin filopodia dynamics, phosphorylated FAK, and altered the cell morphology. Atypical cellular responses could be mimicked with the intracellular kinase domain, which did not activate the Trk-associated MAPK/ERK pathway. In glioblastoma-like U87MG cells, expression of TrkB or SQSTM1-NTRK2 reduced cell motility and caused drastic changes in the transcriptome. Clinically approved Trk inhibitors or mutating Y705 in the kinase domain, blocked the cellular effects and transcriptome changes. Atypical signaling was also seen for TrkA and TrkC. Moreover, hallmarks of atypical pTrk kinase were found in biopsies of Nestin-positive glioblastoma. Therefore, we suggest Western blot-like immunoassay screening of NTRK-related (brain) tumor biopsies to identify patients with atypical panTrk or phosphoTrk signals. Such patients could be candidates for treatment with NTRK inhibitors such as Larotrectinhib or Entrectinhib.

Performances of the Idylla GeneFusion Assay: contribution to a rapid diagnosis of targetable gene fusions in tumour samples

AimsWe aimed to evaluate the performances of the Idylla GeneFusion Assay (IGFA) designed to detect, in a single, rapid and fully automated assay, ALK, ROS1, RET, NTRK1, NTRK2 and NTRK3...