👤 Shuichi Tsutsumi

Hepatocellular carcinoma (HCC) arises from various etiologies, including viral hepatitis and non-viral liver diseases. Although comprehensive genomic profiling (CGP) is increasingly applied in oncology, the influence of disease etiology on the genomic landscape of HCC and biomarker applicability remains insufficiently characterized. CGP data from 551 patients with HCC, registered in the National Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database, were analyzed after excluding cases with undefined etiology. We characterized the mutational landscape, compared mutation frequencies among HBV-, HCV-, and non-viral, non-cholestatic (nBnC)-related HCC, assessed the association between homologous recombination repair (HRR)-related gene alterations and tumor mutation burden (TMB), and evaluated the detection rates of actionable mutations in tissue- versus liquid-based CGP. Telomerase reverse transcriptase splice site mutations were the most common genomic alteration and were consistently observed across all etiologic groups. Although mutations in AXIN1 and DDR2 genes showed modest enrichment in HCV- and HBV-related HCC, respectively, the overall mutational profiles remained largely conserved across etiologies. TMB was significantly lower in nBnC-HCC compared to HCV-related HCC but showed no association with HRR-related mutations. The detection rates of targetable mutations were similar between tissue and liquid biopsies; however, only a small proportion of patients received matched therapies. Real-world data indicate a conserved genomic architecture in HCC regardless of etiology, supporting unified therapeutic approaches. The absence of a relationship between HRR alterations and TMB suggests distinct biological mechanisms. Liquid biopsy remains a reliable option when tissues are unavailable in managing patients with HCC. Show less

GenMineTOP, the first dual DNA-RNA comprehensive genomic profiling (CGP) test in Japan, was approved for reimbursement in 2023. To evaluate its clinical utility, we analyzed 1356 cases from the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database. Oncogenic genomic alterations were identified in 91.5% of cases. Somatic mutations were the most prevalent, followed by amplifications and fusion/exon skipping events. The DNA panel, covering 737 genes, detected not only alterations relevant to therapeutic decisions but also those providing insights into tumor biology. Among the latter, frequently observed examples included mutations in KMT2C (n = 28) and ARID1B (n = 24), and amplifications in GLI1 (n = 14) and YAP1 (n = 10), which are not included in other CGP tests approved in Japan. The RNA panel identified 105 fusion events, including 11 NTRK fusions (0.8%), of which five were NTRK3 fusions: two with the well-known ETV6-NTRK3 fusion and three with non-ETV6 partners. Forty-nine of these fusions were diagnostically significant, highlighting the utility of the RNA panel. Amplification-RNA expression analyses revealed strong correlations for MDM2, CDK4, EGFR, and ERBB2. In contrast, weaker correlations observed for MYC and FGFR1 highlighted the need for careful interpretation of amplification in these genes. Cancer type significantly influenced RNA expression, with KIT and TERT mutations linked to increased expression and significant overexpression observed in ALK, FGFR3, NTRK1, NTRK3, and RET fusions. In summary, this study demonstrated the real-world clinical utility of the dual DNA-RNA CGP test and provided a valuable resource for interpreting RNA expressions. Show less

Teratomas in mice, composed of different tissue types, are derived from primordial germ cells in the fetal gonads. Previously, we identified a locus responsible for experimental testicular teratoma (ETT) formation on chromosome 18, referred to as ett1. The strongest candidate sequence in the ett1 locus was found to be a missense mutation in the melanocortin 4 receptor (Mc4r), Mc4r Show less

Interleukin 27 (IL-27) is a heterodimeric cytokine that functions to constrain T cell-mediated inflammation and plays an important role in immune homeostasis. Binding of IL-27 to cell surface receptors, IL-27Rα and gp130, results in activation of receptor-associated Janus Kinases and nuclear translocation of Signal Transducer and Activator of Transcription 1 (STAT1) and STAT3 transcription factors. Despite the emerging therapeutic importance of this cytokine axis in cancer and autoimmunity, a molecular blueprint of the IL-27 receptor signaling complex, and its relation to other gp130/IL-12 family cytokines, is currently unclear. We used cryogenic-electron microscopy to determine the quaternary structure of IL-27, composed of p28 and Epstein-Barr Virus-Induced 3 (Ebi3) subunits, bound to receptors, IL-27Rα and gp130. The resulting 3.47 Å resolution structure revealed a three-site assembly mechanism nucleated by the central p28 subunit of the cytokine. The overall topology and molecular details of this binding are reminiscent of IL-6 but distinct from related heterodimeric cytokines IL-12 and IL-23. These results indicate distinct receptor assembly mechanisms used by heterodimeric cytokines with important consequences for targeted agonism and antagonism of IL-27 signaling. Show less

The exchange of genetically engineered mouse strains between research facilities requires transporting fresh mouse sperm under refrigerated temperatures. Although sperm generally maintains fertility for 48 h at cold temperatures, in vitro fertilization rates of C57BL/6 mouse sperm are low after 48-h cold storage. Furthermore, 48 h is often not sufficient for the specimens to reach their destinations. To increase the availability of this technology, we aimed to extend the cold storage period while maintaining sperm fertility. In this study, we determined the optimal medium for sperm preservation and evaluated the effect of reduced glutathione in the fertilization medium on sperm fertility after cold storage. We found that higher fertility levels were maintained after 72-h cold storage in the preservation medium Lifor compared with storage in paraffin oil, M2 medium, or CPS-1 medium. In addition, 1.0 mM glutathione enhanced sperm fertility. After transporting sperm from Asahikawa Medical University to our laboratory, embryos were efficiently produced from the cold-stored sperm. After transfer, these embryos developed normally into live pups. Finally, we tested the transport system using genetically engineered mouse strains and obtained similar high fertilization rates with all specimens. In summary, we demonstrated that cold storage of sperm in Lifor maintains fertility, and glutathione supplementation increased the in vitro fertilization rates of sperm after up to 96 h of cold storage. This improved protocol provides a simple alternative to transporting live animals or cryopreserved samples for the exchange of genetically engineered mouse strains among research facilities. Show less

Long-range regulatory elements and higher-order chromatin structure coordinate the expression of multiple genes in cluster, and CTCF/cohesin-mediated chromatin insulator may be a key in this regulation. The human apolipoprotein (APO) A1/C3/A4/A5 gene region, whose alterations increase the risk of dyslipidemia and atherosclerosis, is partitioned at least by three CTCF-enriched sites and three cohesin protein RAD21-enriched sites (two overlap with the CTCF sites), resulting in the formation of two transcribed chromatin loops by interactions between insulators. The C3 enhancer and APOC3/A4/A5 promoters reside in the same loop, where the APOC3/A4 promoters are pointed towards the C3 enhancer, whereas the APOA1 promoter is present in the different loop. The depletion of either CTCF or RAD21 disrupts the chromatin loop structure, together with significant changes in the APO expression and the localization of transcription factor hepatocyte nuclear factor (HNF)-4alpha and transcriptionally active form of RNA polymerase II at the APO promoters. Thus, CTCF/cohesin-mediated insulators maintain the chromatin loop formation and the localization of transcriptional apparatus at the promoters, suggesting an essential role of chromatin insulation in controlling the expression of clustered genes. Show less