Heterogeneity Of Mutations Research Articles

Mutational heterogeneity in large B-cell lymphoma: insights from paired biopsies.

Large B-cell lymphoma (LBCL) exhibits striking clinical and molecular heterogeneity. New approaches have emerged to explore tumor heterogeneity and classify LBCL into biological categories. Consequently, the informational requirements from diagnostic samples to provide the necessary information have increased, but the adequacy of single-site biopsies to provide such information is largely unknown. Here we describe spatial and temporal intra-patient variations in the mutational landscape of paired biopsies. Paired biopsies from 30 patients with LBCL were obtained from spatially distinct sites at the time of primary diagnosis before treatment and/or at a subsequent relapse. The samples were sequenced using a custom designed 59-gene next generation sequencing (NGS) lymphoma panel. Differences in detected mutations of pathogenic or likely pathogenic significance were frequent both when comparing paired diagnostic biopsies, 2/6 (33%), and when comparing paired biopsies at primary diagnosis and relapse, 8/16 (50%). Mutational heterogeneity tended to increase with longer time interval between biopsies. Analysis of paired diagnostic and relapse biopsies revealed that certain clones present at diagnosis disappeared, while new clones emerged at relapse. Notably, TP53 mutations were detected in six out of seven patients in an extranodal location. In two cases, TP53 mutation was only detected in the relapse biopsy. Several of the mutations identified in this study are used or under investigation as targets for cancer treatments. Multi-site biopsies revealed spatial and temporal mutational heterogeneity in patients with LBCL. Our findings indicate that mutational differences between biopsy pairs can occur at all timepoints examined. This underscores the necessity of performing repeat biopsies with each relapse to capture the full spectrum of genetic aberrations.

DNA Repair and Replicative Stress Addiction in Neuroblastoma

Neuroblastoma (NB) is a pediatric tumor of the sympathetic nervous system. Survival remains poor for the almost 40% of patients with high-risk NB. Targeted therapy options for high-risk NB are limited and single compound strategies often fail due to escape mechanisms, driven either by tumor heterogeneity or adaptive (epigenetic) responses or mutations. Novel NB therapeutic approaches rely increasingly on biomarker selected cohorts for phase I/II clinical trials. Parallel intensive research programs are needed to identify novel therapeutic vulnerabilities or drug targeting strategies and to further inform clinical trials and prioritize potent, less toxic combinations. While several effective chemotherapies work by increasing replication stress in cancer cells, recently, newer putatively less toxic small molecule-based approaches that directly target DNA damage response (DDR) pathway components such as ATR, CHK1 and PARP inhibitors are being evaluated in early phase trials for many cancers. NB sequencing studies have identified recurrent alterations (copy number and mutations) in many of these genes encoding critical DDR pathway proteins suggesting susceptibility to specific classes of DDR-targeting therapies. In this review, we summarize current data supporting the roles of DDR and replicative stress addiction in NB, including genetic alterations which impact DDR signaling pathways. Finally, we review the mechanisms, pre-clinical evidence and ongoing trials for drugs that target DDR-deficient and/or replication addicted NB.

Evaluation of Heterogeneity in the Coding Region of BRAF, MAP2K1, and MAP2K2 Genes in Primary and Metastatic Melanomas.

The incidence of melanoma has been increasing in recent decades. BRAF mutations appear in 50%-70% of melanomas. The BRAF-targeted therapy increased the disease-free survival of patients with metastatic melanoma, but this response may be short, due to several resistance mechanisms, such as the presence of other subclones with mutations. Evaluation of mutations and heterogeneity in the coding region of the BRAF, MAP2K1, and MAP2K2 genes in primary and metastatic melanomas. Twenty-seven samples of primary and metastatic superficial spreading melanoma (SSM) and acral lentiginous melanoma (ALM) were analyzed for BRAF, MAP2K1, and MAP2K2 mutations using the next-generation sequencing technique. In ALM, the mutation rate found was 50% in the BRAF and MAP2K1 genes and 28.6% in MAP2K2. In the SSM, BRAF was mutated in 76.9%, MAP2K1 in 30.8%, and MAP2K2 in 23.2% of the cases. All samples were formed by distinct tumor subclones in the same lesion. Intertumoral heterogeneity was present between primary and metastatic lesions of ALM in BRAF, MAP2K1, and MAP2K2; the cases of SSM were heterogeneous for BRAF and MAP2K1. We sought to evaluate the mutations in the BRAF, MAP2K1, and MAP2K2 genes, revealing a heterogeneous mutation profile in samples of ALM and SSM.

Prognostic characteristics and drug sensitivity analysis of hepatocellular carcinoma based on histone modification-related genes: a multi-omics integrated study revealing potential therapeutic targets and individualized treatment strategies.

Hepatocellular carcinoma (HCC) ranks among the most prevalent and lethal malignancies worldwide. Histone modifications (HMs) play a pivotal role in the initiation and progression of HCC. However, our understanding of HMs in HCC remains limited due to the disease's heterogeneity and the complexity of HMs. We integrated multi-omics data from multiple cohorts, including single-cell RNA sequencing, bulk RNA sequencing, and clinical information. Weighted gene co-expression network analysis (WGCNA) and consensus clustering were employed to identify histone-related genes. We developed a histone modification-related signature (HMRS) using 117 machine learning methods. Comprehensive analyses of molecular characteristics, immune landscape, and drug sensitivity associated with the HMRS were performed. Through integrative analysis, we defined 110 histone-related genes and identified 45 HCC-HM-related genes (HCC-HMRgenes). The HMRS demonstrated robust prognostic value across multiple cohorts. Patients with high HMRS scores exhibited distinct genomic alterations, including higher tumor heterogeneity and TP53 mutations. The high-risk group showed enrichment in cell cycle, DNA repair, and metabolic pathways. Immune landscape analysis revealed significant differences in immune cell infiltration and pathway activities between high- and low-risk groups. Drug sensitivity prediction suggested potential therapeutic strategies for different risk groups. Our study provides a comprehensive understanding of HMs in HCC and establishes a robust prognostic signature. The HMRS not only stratifies patients into distinct risk groups but also offers insights into underlying molecular mechanisms, immune characteristics, and potential therapeutic strategies, paving the way for personalized medicine in HCC.

TP53 Mutation Heterogeneity Reveals Distinct Prognoses in Mantle Cell Lymphoma

TP53 Mutation Heterogeneity Reveals Distinct Prognoses in Mantle Cell Lymphoma

Genetic Characteristics of Cutaneous, Acral, and Mucosal Melanoma in Japan.

Acral and mucosal melanomas are more prevalent in Asians than in Caucasians, unlike cutaneous melanomas, which are predominant in Caucasians. Recent studies have suggested that non-Caucasian cutaneous melanomas responded less to immune checkpoint inhibitors, highlighting the need for genetic profiling across ethnicities. This study aimed to elucidate the genetic characteristics of Japanese melanomas, which is an under-researched topic. Single-nucleotide variants, indels, and copy number alterations in 104 Japanese melanoma patients (37 cutaneous, 52 acral, and 15 mucosal) were analyzed using custom panel sequencing. Driver events were detected in 94% of the cases. Among cutaneous melanoma cases, 76% had BRAF mutations, and 8% had NRAS mutations. In acral melanoma, BRAF (9%), NRAS (17%), KRAS (8%), KIT (19%), and NF1 (7%) mutations were detected. Major driver mutations in mucosal melanoma were detected in NRAS, KRAS, NF1, PTEN, GNAQ, and KIT. The median tumor mutational burden across all melanoma types was 4.6 mutations/Mb, with no significant difference between the cutaneous and acral/mucosal types. Of the 21 patients with both primary and metastatic lesions, 11 showed distinct mutations in each. Potentially actionable mutations were detected in 58 patients in addition to BRAF V600E/K mutations in 31. This study highlights distinct genetic abnormalities and actionable alterations in Japanese melanoma patients. This suggests a lower tumor mutational burden in East Asian cutaneous melanoma, which may affect the efficacy of immune checkpoint inhibitors. The heterogeneity of driver mutations across and within individuals highlights the need for personalized treatment approaches.

Gastric Epithelial Neoplasm of Fundic-Gland Mucosa Lineage: Showed the Same Genetic Lineage and Ki67 May Help in Their Identification

Abstract Introduction/Objective Gastric epithelial neoplasm of the fundic-gland mucosa lineages (GEN-FGMLs) are rare form of gastric tumors that encompasses oxyntic gland adenoma (OGA), gastric adenocarcinoma of the fundic-gland type (GA-FG), and gastric adenocarcinoma of the fundic-gland mucosa type (GA-FGM). There is no consensus on the clinicopathologica and molecular characteristics of GEN-FGMLs, and misdiagnosis is common because of similarities in symptoms. Methods/Case Report The NGS and immunohistochemical staining were performed on 37 cases diagnosed with GEN-FGMLs with a thorough histological evaluation. Gene alternations were analysed and compared across histological subtypes. we used an artificial intelligence approach for the recognition of the Ki67 immunohistochemistry stained. Results (if a Case Study enter NA) The patient’s ages ranged from 42 to 79 years, with a median age of 60. 17 were male and 20 were female. Morphologically, 19 OGAs, 16 GA-FGs, and two GA-FGMs were identified. Histopathological similarities exist between GEN-FGMLs. The tumors demonstrated well-formed glands, expanding with dense growth patterns comprising pale, blue-grey columnar cells with mild nuclear atypia. The normal gastric pit epithelium covered the entire surface of the OGA and GA-FG, but the dysplasia pit epithelium covered the GA-FGM. Compared with OGA, GA-FG and GA-FGM were more prominent in the macroscopic view (p<0.05) and had larger sizes (p<0.0001). Additionally, GA-FG and GA-FGM exhibited higher Ki67 indices than OGA (p<0.0001). The heterogeneity of mutational signatures, somatic mutations, and copy number variations was revealed across histological subtypes. The top five mutational signatures in OGA were ROS1, CTNNA1, GNAS, BRCA2, and ZFHX3. The top five mutational signatures in GA-FG and GA-FGM were GNAS, MLL3, BRAF, MSH3, and EGFR. GNAS were both found in OGA, GA-FG and GA-FGM. Compared with well-differencent gastric adenocarcinoma, The top five mutational signatures in GEN-FGMLs were GNAS, BRAF, ROS1, MLL3, and MSH3. Recurrently mutated key signaling pathways across tumor types in GEN-FGML were Wnt signaling pathways. Conclusion GEN-FGMLs are a group of well-differentiated gastric tumors with favourable biological behaviours. Compared with OGA, GA-FG and GA-FGM have larger sizes and higher Ki67 proliferation indices, indicating that they play a critical role in the identification of GEN-FGML. GEN-FGMLs showed the same genetic lineage, the Wnt signalling pathway plays a role in the development and progression of GEN-FGMLs.

Novel human PDX1 Asn196Thr variant causes pancreas agenesis and reduces the generation of duodenal enteroendocrine cells

Abstract Introduction/Objective Pancreatic and duodenal homeobox 1 (PDX1) is a well-studied transcription factor required for pancreas organogenesis. PDX1 mutations are associated with the development of diabetes. An 8-month-old female patient with previously uncharacterized compound heterogeneous PDX1 missense mutations (Thr151Met and Asn196Thr) was identified in this study. The patient has permanent neonatal diabetes, pancreas hypoplasia, and a malformed gallbladder. Methods/Case Report PDX1 Thr151Met and Asn196Thr variants in the patient were identified by next-generation sequencing gene panel and confirmed by Sanger sequencing. To examine how the mutations affect PDX1 functions in vitro, we expressed mouse Pdx1 Thr152Met and Asn197Thr, homologous to human PDX1 Thr151Met and Asn196Thr, respectively, in mouse insulinoma MIN6 cells and human embryonic kidney 293T cells and examined protein localization, protein stability, DNA binding, and protein-protein interaction. We also generated embryonic day 18 mouse embryos carrying Pdx1 Asn197Thr missense mutation using CRISPR/Cas9 to examine its roles in the development of the pancreas and other digestive organs in vivo. Results (if a Case Study enter NA) We found that the Pdx1 Asn197Thr variant, but not Thr152Met, altered its nuclear localization and disrupted PDX1-Onecut 1 interaction. Neither variant significantly affected PDX1 protein stability, but both reduced PDX1 binding to the Pdx1 gene promoter. Importantly, we found that the Pdx1 Asn197Thr variant caused pancreas agenesis and a reduction in the generation of enteroendocrine cells in the proximal duodenum in mouse models. Conclusion Our data indicated that the PDX1 Asn196Thr variant impairs its DNA binding and protein-protein interaction, causing pancreas agenesis and a reduction in the generation of duodenal enteroendocrine cells.

Late-onset renal TMA and tubular injury in cobalamin C disease: a report of three cases and literature review

BackgroundMutation of MMACHC gene causes cobalamin C disease (cblC), an inherited metabolic disorder, which presents as combined methylmalonic aciduria (MMA-uria) and hyperhomocysteinaemia in clinical. Renal complications may also be present in patients with this inborn deficiency. The most common histological change is thrombotic microangiopathy (TMA). However, to our acknowledge, renal tubular injury in the late-onset presentation of cblC is rarely been reported. This study provides a detailed description of the characteristics of kidney disease in cblC deficiency, aiming to improve the early recognition of this treatable disease for clinical nephrologists.Case presentationHere we described three teenage patients who presented with hematuria, proteinuria, and hypertension in clinical presentation. They were diagnosed with renal involvement due to cblC deficiency after laboratory tests revealing elevated serum and urine homocysteine, renal biopsy showing TMA and tubular injury, along with genetic testing showing heterogeneous compound mutations in MMACHC. Hydroxocobalamin, betaine, and L-carnitine were administered to these patients. All of them got improved, with decreased homocysteine, controlled blood pressure, and kidney outcomes recovered.ConclusionsThe clinical diagnosis of cblC disease associated with kidney injury should be considered in patients with unclear TMA accompanied by a high concentration of serum homocysteine, even in teenagers or adults. Early diagnosis and timely intervention are vital to improving the prognosis of cobalamin C disease.Clinical Trial NumberNot applicable.

Retinal Proteome Profiling of Inherited Retinal Degeneration Across Three Different Mouse Models Suggests Common Drug Targets in Retinitis Pigmentosa

Inherited retinal degenerations (IRDs) are a leading cause of blindness among the population of young people in the developed world. Approximately half of IRDs initially manifest as gradual loss of night vision and visual fields, characteristic of retinitis pigmentosa (RP). Due to challenges in genetic testing, and the large heterogeneity of mutations underlying RP, targeted gene therapies are an impractical largescale solution in the foreseeable future. For this reason, identifying key pathophysiological pathways in IRDs that could be targets for mutation-agnostic and disease-modifying therapies (DMTs) is warranted. In this study, we investigated the retinal proteome of three distinct IRD mouse models, in comparison to sex- and age-matched wild-type mice. Specifically, we used the Pde6βRd10 (rd10) and RhoP23H/WT (P23H) mouse models of autosomal recessive and autosomal dominant RP, respectively, as well as the Rpe65-/- mouse model of Leber's congenital amaurosis type 2 (LCA2). The mice were housed at two distinct institutions and analyzed using LC-MS in three separate facilities/instruments following data-dependent and data-independent acquisition modes. This cross-institutional and multi-methodological approach signifies the reliability and reproducibility of the results. The large-scale profiling of the retinal proteome, coupled with invivo electroretinography recordings, provided us with a reliable basis for comparing the disease phenotypes and severity. Despite evident inflammation, cellular stress, and downscaled phototransduction observed consistently across all three models, the underlying pathologies of RP and LCA2 displayed many differences, sharing only four general KEGG pathways. The opposite is true for the two RP models in which we identify remarkable convergence in proteomic phenotype even though the mechanism of primary rod death in rd10 and P23H mice is different. Our data highlights the cAMP and cGMP second-messenger signaling pathways as potential targets for therapeutic intervention. The proteomic data is curated and made publicly available, facilitating the discovery of universal therapeutic targets for RP.

Annual change in eGFR in renal hypouricemia: a retrospective pilot study.

Extremely low uric acid (UA) levels or increased urinary UA (Uua) excretion might be risk factors for kidney disease in renal hypouricemia (RHU) patients, but their relationship with kidney dysfunction is unclear. This study investigated time-dependent changes in eGFR in RHU patients. This multicenter retrospective study assessed UA metabolism and changes in eGFR (median 5.5years) in 13 RHU patients. We then compared eGFR change in 7 of 13 RHU patients whose eGFR could be measured for 4years with those in normouricemic group (n = 31). In addition, 7 RHU patients were divided into two groups based on URAT1 gene mutations: homozygote and compound heterozygote mutations (Homo/Com group, n = 3), and wild-type and heterogeneous mutations (WT/Hetero group, n = 4). In 13 RHU patients, the median and mean serum UA (SUA) were 0.8 (0.4-2.5) and 1.1 ± 0.7mg/dL. The median and mean Uua were 44.3 (12.7-141.1) and 49.7 ± 36.2mg/dL. The median and mean urinary urate clearance (Cua/Ccr) were 46.8 (11.3-73.6) and 43.3 ± 19.7%. Over 4years, eGFR did not change in the RHU group but declined in the normouricemic group. Annual mean eGFR decline and change rate in the RHU group were the same as those in the normouricemic group (- 1.09 ± 1.11 vs. - 1.09 ± 1.92mL/min/1.73 m2/year, p = 0.996) (- 1.74 ± 1.96 vs. - 1.36 ± 2.10%, p = 0.664). And no significant difference was found in eGFR decline or change rate between Homo/Com and WT/Hetero groups (- 0.33 ± 1.03 vs. - 1.67 ± 0.85mL/min/1.73 m2/year, p = 0.116) (- 0.61 ± 1.62 vs. - 2.59 ± 1.91%, p = 0.210). RHU from URAT1 genetic mutation may not show eGFR decline over 4 consecutive years.

Measurable residual disease monitoring in AML with FLT3-ITD treated with intensive chemotherapy plus midostaurin

AbstractMeasurable residual disease (MRD) monitoring in acute myeloid leukemia (AML) with an FLT3 internal tandem duplication (FLT3-ITDpos) has been hampered by the broad heterogeneity of ITD mutations. Using our recently developed FLT3-ITD paired-end next-generation sequencing (NGS)–based MRD assay (limit of detection 10−4 to 10−5), we evaluated the prognostic impact of MRD at different time points in 157 patients with FLT3-ITDpos AML who were enrolled in the German-Austrian Acute Myeloid Leukemia Study Group 16-10 trial and who were treated with a combination of intensive chemotherapy and midostaurin, followed by midostaurin maintenance. MRD negativity (MRDneg) after 2 cycles of chemotherapy (Cy2), which was observed in 111 of 142 (78%) patients, was predictive of superior 4-year rates of cumulative incidence of relapse (CIR) (4y-CIR; 26% vs 46%; P = .001) and overall survival (OS) (4y-OS; 70% vs 44%; P = .012). This survival advantage was also seen among patients who underwent allogeneic hematopoietic-cell transplantation during first complete remission (4y-CIR, 14% vs 39%; P = .001; 4y-OS, 71% vs 49%; P = .029). Multivariate models for CIR and OS after Cy2 revealed FLT3-ITD MRDneg as the only consistent favorable variable for CIR (hazard ratio [HR], 0.29; P = .006) and OS (HR, 0.39; P = .018). During follow-up, conversion from MRDneg to MRD positivity (MRDpos) was a strong, independent factor for inferior CIR (HR, 16.64; P < .001) and OS (HR, 4.05; P < .001). NGS-based FLT3-ITD MRD monitoring identifies patients at high risk for relapse and death following treatment with intensive chemotherapy and midostaurin. Using NGS-based technology.

Advancing cancer driver gene identification through an integrative network and pathway approach

ObjectiveCancer is a complex genetic disease characterized by the accumulation of various mutations, with driver genes playing a crucial role in cancer initiation and progression. Distinguishing driver genes from passenger mutations is essential for understanding cancer biology and discovering therapeutic targets. However, the majority of existing methods ignore the mutational heterogeneity and commonalities among patients, which hinders the identification of driver genes more effectively. MethodsThis study introduces MCSdriver, a novel computational model that integrates network and pathway information to prioritize the identification of cancer driver genes. MCSdriver employs a bidirectional random walk algorithm to quantify the mutual exclusivity and functional relationships between mutated genes within patient cohorts. It calculates similarity scores based on a mutual exclusivity-weighted network and pathway coverage patterns, accounting for patient-specific heterogeneity and molecular profile similarity. ResultsThis approach enhances the accuracy and quality of driver gene identification. MCSdriver demonstrates superior performance in identifying cancer driver genes across four cancer types from The Cancer Genome Atlas, showing a higher F-score, Recall and Precision compared to existing ranking list-based and module-based models. ConclusionThe MCSdriver model not only outperforms other models in identifying known cancer driver genes but also effectively identifies novel driver genes involved in cancer-related biological processes. The model’s consideration of patient-specific heterogeneity and similarity in molecular profiles significantly enhances the accuracy and quality of driver gene identification. Validation through Gene Ontology enrichment analysis and literature mining further underscores its potential application value in personalized cancer therapy, offering a promising tool for advancing our understanding and treatment of cancer.

VHL missense mutation delineate aggressive clear cell renal cell carcinoma subtype with favorable immunotherapeutic response

Backgroundvon Hippel-Lindau (VHL) harbors the highest mutational frequency in clear cell renal cell carcinoma (ccRCC). Although VHL mutational subtypes exert diverse impacts on the functionality of the VHL protein, the...

The RAS/BRAF genes status in patients with colorectal cancer (review)

Colorectal cancer (CRC) is the third in prevalence among oncological diseases worldwide and second in the structure of oncological mortality. Genetic assessment of CRC is a necessary stage during selecting further treatment for patients. Many studies demonstrate a diverse distribution of mutations in the KRAS, NRAS, and BRAF genes in CRC. A critical literature review was conducted in order to systematize data on the mutational profile and genetic heterogeneity of these driver mutations in Russian patients with CRC. Articles were searched for in open databases. Totally 17 Russian studies and 3 English meta-analyses were analyzed for comparison with Russian data. Mutations in the KRAS, NRAS, and BRAF genes, according to Russian and international studies, are found in 40 %, 4 %, and 7 % in CRC patients, respectively. The frequency and specific localization of mutations may depend on the geographical location and nationality of the cohort. High intertumoral and intratumoral heterogeneity in CRC, especially in KRAS gene mutations, significantly influences the choice of further therapy and underscores the need for more detailed study of the mutational profile of the primary tumor, affected lymph nodes, and distant metastases. In Russia, several molecular genetic methods are used to determine somatic mutations in CRC with different sensitivity and specificity, the most common is real-time PCR. More accurate diagnostic methods include digital droplet PCR, Sanger sequencing, and next-generation sequencing, but each method has its limitations that must be considered when planning diagnostics and research. The promising directions in personalized oncology is the study of gene copy number variations, which may contribute to the development of new methods for treating CRC in the future. Despite the large number of studies, some aspects of the mutational profile of CRC in Russian studies remain poorly understood, which is why further research is needed on patients with colorectal cancer in Russia.

Diet and Nutrients in Rare Neurological Disorders: Biological, Biochemical, and Pathophysiological Evidence.

Background/Objectives: Rare diseases are a wide and heterogeneous group of multisystem life-threatening or chronically debilitating clinical conditions with reduced life expectancy and a relevant mortality rate in childhood. Some of these disorders have typical neurological symptoms, presenting from birth to adulthood. Dietary patterns and nutritional compounds play key roles in the onset and progression of neurological disorders, and the impact of alimentary needs must be enlightened especially in rare neurological diseases. This work aims to collect the in vitro, in vivo, and clinical evidence on the effects of diet and of nutrient intake on some rare neurological disorders, including some genetic diseases, and rare brain tumors. Herein, those aspects are critically linked to the genetic, biological, biochemical, and pathophysiological hallmarks typical of each disorder. Methods: By searching the major web-based databases (PubMed, Web of Science Core Collection, DynaMed, and Clinicaltrials.gov), we try to sum up and improve our understanding of the emerging role of nutrition as both first-line therapy and risk factors in rare neurological diseases. Results: In line with the increasing number of consensus opinions suggesting that nutrients should receive the same attention as pharmacological treatments, the results of this work pointed out that a standard dietary recommendation in a specific rare disease is often limited by the heterogeneity of occurrent genetic mutations and by the variability of pathophysiological manifestation. Conclusions: In conclusion, we hope that the knowledge gaps identified here may inspire further research for a better evaluation of molecular mechanisms and long-term effects.

Intratumoral heterogeneity of oncogenic drivers in mixed histology lung adenocarcinomas: How tissue selection impacts molecular testing?

Majority of the lung adenocarcinomas show a mixture of different histological patterns. The possibility of histologically heterogeneous areas of the adenocarcinoma showing genetic heterogeneity and harboring different driver mutations, with potentially significant clinical impact, has not been adequately addressed. Currently, there are no guidelines to suggest how to submit tumor tissue in adenocarcinomas with mixed histological features for molecular testing.The objective of this study is to assess intra-tumoral heterogeneity in prominent driver mutations among different morphological patterns of lung adenocarcinoma, its implications on the future of molecular testing as well as its potential impact on patient management.Twenty-three cases of mixed histology lung adenocarcinoma resected between 2018 and 2023 were retrieved from the archives. H&E slides were reviewed to identify the predominant and second most predominant histological patterns. The morphologically different tumor areas were manually macro-dissected for DNA extraction. Next-Generation Sequencing with Ion AmpliSeq™ Cancer Hotspot Panel v2 (Thermo Fisher Scientific, USA).Thirteen cases showed the same pathological variant in both histological components tested. Three cases (13 %) exhibited disparities in the variants detected across the different histological patterns tested (p=0.025). The discrepant findings had a direct therapeutic impact in 4.3 % cases. Seven cases showed no pathogenic variants detected on either of the histological components tested.This study elucidates the presence of infrequent yet significant intra-tumoral heterogeneity in the molecular profiles of mixed histology adenocarcinomas, highlighting the need for guidelines directing tissue selection for molecular testing to avoid missed therapeutic opportunities and mitigate disease relapse.

1288P Clinical impact and landscape of heterogeneous ALK resistance mutations (muts) after comprehensive genomic profiling (CGP)

1288P Clinical impact and landscape of heterogeneous ALK resistance mutations (muts) after comprehensive genomic profiling (CGP)

Clinical, Laboratory, and Molecular Aspects of Factor VII Deficiency.

Congenital factor VII (FVII) deficiency, the most frequent among the recessively inherited disorders of blood coagulation, is characterized by a wide range of symptoms, from mild mucosal bleeds to life-threatening intracranial hemorrhage. Complete FVII deficiency may cause perinatal lethality. Clinically relevant thresholds of plasma levels are still uncertain, and modest differences in low FVII levels are associated with large differences in clinical phenotypes. Activated FVII (FVIIa) expresses its physiological protease activity only in a complex with tissue factor (TF), which triggers clotting at a very low concentration. Knowledge of the FVIIa-TF complex helps to interpret the clinical findings associated with low FVII activity as compared with other rare bleeding disorders and permits effective management, including prophylaxis, with recombinant FVIIa, which, however, displays a short half-life. Newly devised substitutive and nonsubstitutive treatments, characterized by extended half-life properties, may further improve the quality of life of patients. Genetic diagnosis has been performed in thousands of patients with FVII deficiency, and among the heterogeneous F7 mutations, mostly missense changes, several recurrent variants show geographical distribution and identity by descent. In the general population, common F7 polymorphisms explain a large proportion of FVII level variance in plasma through FVII-lowering effects. Their combination with pathogenic variants may impact on the frequent detection of FVII coagulant levels lower than normal, as well as on mild bleeding conditions. In the twenties of this century, 70 years after the first report of FVII deficiency, more than 200 studies/reports about FVII/FVII deficiency have been published, with thousands of FVII-deficient patients characterized all over the world.

Interaction between the TBC1D24 TLDc domain and the KIBRA C2 domain is disrupted by two epilepsy-associated TBC1D24 missense variants

Mutations of human TBC1D24 are associated with either deafness, epilepsy or DOORS syndrome (deafness, onychodystrophy, osteodystrophy, cognitive disability, seizures). The causal relationships between TBC1D24 variants and the different clinical phenotypes are not understood. Our hypothesis is that phenotypic heterogeneity of missense mutations of TBC1D24 results, in part, from perturbed binding of different protein partners. To discover novel protein partners of TBC1D24, we conducted a yeast two-hybrid (Y2H) screen using mouse full-length (FL) TBC1D24 as bait. KIBRA, a scaffold protein encoded by Wwc1, was identified as a partner of TBC1D24. KIBRA functions in the Hippo signaling pathway and is important for human cognition and memory. The TBC1D24 TLDc domain binds to KIBRA FL and to its C2 domain, confirmed by Y2H assays. No interaction was detected with Y2H assays between the KIBRA C2 domain and TLDc domains of NCOA7, MEAK7 and OXR1. Moreover, the C2 domains of other WWC family proteins do not interact with the TLDc domain of TBC1D24, demonstrating specificity. The mRNAs encoding TBC1D24 and KIBRA proteins in mouse are coexpressed at least in a subset of hippocampal cells indicating availability to interact in vivo. As two epilepsy-associated recessive variants (Gly511Arg and Ala515Val) in the TLDc domain of human TBC1D24 disrupt the interaction with human KIBRA C2 domain, this study reveals a pathogenic mechanism of TBC1D24-associated epilepsy, linking the TBC1D24 and KIBRA pathways. The interaction of TBC1D24-KIBRA is physiologically meaningful and necessary to reduce the risk of epilepsy.