Publications by authors named "Sun Ha Paek"

Chronic neuroinflammation is a principal cause of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. The blood-brain barrier predominantly comprises endothelial cells, and their intercellular communication with pericytes and other cell types regulates neuroinflammation. Here, we develop a tubular, perfusable model of human cerebrovascular tissues to study neurodegenerative diseases using cerebrovascular-specific extracellular matrix bioink, derived from a complementary blend of brain- and blood-vessel-derived extracellular matrices.

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To understand the role of extrachromosomal DNA (ecDNA) amplifications in cancer progression, we detected and classified focal amplifications in 8,060 newly diagnosed primary cancers, untreated metastases and heavily pretreated tumors. The ecDNAs were detected at significantly higher frequency in untreated metastatic and pretreated tumors compared to newly diagnosed cancers. Tumors from chemotherapy-pretreated patients showed significantly higher ecDNA frequency compared to untreated cancers.

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Background: We aimed to evaluate long-term outcomes of gamma knife radiosurgery (GKS) for cerebral cavernous malformations (CCMs).

Methods: Among the 233 CCM patients who underwent GKS, 79 adult patients (96 lesions) followed for over 10 years were included and analyzed retrospectively. Annual hemorrhage rate (AHR) was analyzed the entire cohort of 233 patients and the subset of 79 enrolled patients by dividing lesions into overall CCM lesions and brainstem lesions.

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Objectives: To evaluate the treatment outcomes in patients with advanced-stage olfactory neuroblastoma (ONB) who received induction chemotherapy (IC).

Materials And Methods: The clinical data of 38 patients with advanced-stage ONB who received initial IC were retrospectively analyzed. The response was defined using the Response Evaluation Criteria in Solid Tumors version 1.

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Article Synopsis
  • * Results indicated that obliteration rates improved with higher doses for AVMs between 10-30 mL and required multiple GKS sessions, while AVMs over 30 mL showed no improvement with the first treatment.
  • * The complication rate was manageable, with an overall obliteration rate of 61.5% and significant factors affecting outcomes including AVM volume and radiation dose.
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Objectives: To investigate the potential relationship between trastuzumab emtansine (T-DM1) treatment and radionecrosis induced by brain stereotactic radiosurgery (SRS) in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer.

Materials And Methods: Patients with HER2-positive breast cancer who were diagnosed with brain metastasis and received both SRS and HER2-targeted agents between 2012 and 2022 were retrospectively analyzed. Patients who received T-DM1 within 1 year (either before or after) of SRS were considered as 'T-DM1 exposure (+)'.

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Article Synopsis
  • NTRK gene fusions occur in about 1% of gliomas and are considered promising targets for treatment due to their ability to cross the blood-brain barrier, leading to interest in TRK inhibitors.
  • A study of 12 NGS-verified NTRK-fused gliomas at Seoul National University Hospital found that DLGGs mostly had only NTRK fusions, while DHGGs often had additional genetic mutations, with various fusion partners identified for NTRK1 and NTRK2.
  • Treatment outcomes using TRK inhibitors varied significantly; one child with DLGG showed stable disease, while a child with DHGG and an adult with glioblastoma experienced tumor recurrence and progression, highlighting the mixed
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Objective: Obsessive-compulsive disorder (OCD) is a psychiatric condition that causes significant distress and social costs and often follows a chronic course with frequent relapses. Approximately 20% of patients do not respond to medication or cognitive behavioral therapy; gamma knife surgery (GKS) has been proposed as a treatment option for these patients. However, research on GKS for OCD patients is rare.

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Tumor microenvironment is intrinsically hypoxic with abundant hypoxia-inducible factors-1α (HIF-1α), a primary regulator of the cellular response to hypoxia and various stresses imposed on the tumor cells. HIF-1α increases radioresistance and chemoresistance by reducing DNA damage, increasing repair of DNA damage, enhancing glycolysis that increases antioxidant capacity of tumors cells, and promoting angiogenesis. In addition, HIF-1α markedly enhances drug efflux, leading to multidrug resistance.

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Glioblastoma (GBM), the most lethal primary brain cancer, exhibits intratumoral heterogeneity and molecular plasticity, posing challenges for effective treatment. Despite this, the regulatory mechanisms underlying such plasticity, particularly mesenchymal (MES) transition, remain poorly understood. In this study, we elucidate the role of the RNA-binding protein ELAVL2 in regulating aggressive MES transformation in GBM.

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  • The study analyzed the epigenetic changes in gliomas from 132 patients over time, comparing initial and recurrent tumors in both IDH-wildtype (IDHwt) and IDH-mutant (IDHmut) types.
  • IDHwt gliomas remained stable in their epigenetic profile, while IDHmut gliomas showed a notable decrease in DNA methylation, making their profiles more similar to IDHwt tumors.
  • The research identified HOXD13 as crucial for the evolution of IDHmut tumors and found that treatment led to changes in the tumor microenvironment, like increased blood vessel formation and T-cell presence, mimicking the characteristics of IDHwt gliomas.
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Patient-derived xenograft (PDX) models, which can retain the characteristics of original tumors in an in vivo-mimicking environment, have been developed to identify better treatment options. However, although original tumors and xenograft tissues mostly share oncogenic mutations and global gene expression patterns, their detailed mutation profiles occasionally do not overlap, indicating that selection occurs in the xenograft environment. To understand this mutational alteration in xenografts, we established 13 PDX models derived from 11 brain tumor patients and confirmed their histopathological similarity.

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Background: This study aims to elucidate clinical features, therapeutic strategies, and prognosis of pineal parenchymal tumors (PPT) by analyzing a 30-year dataset of a single institution.

Methods: We reviewed data from 43 patients diagnosed with PPT at Seoul National University Hospital between 1990 and 2020. We performed survival analyses and assessed prognostic factors.

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Glioblastoma is one of the most malignant primary brain cancer. Despite surgical resection with modern technology followed by chemo-radiation therapy with temozolomide, resistance to the treatment and recurrence is common due to its aggressive and infiltrating nature of the tumor with high proliferation index. The median survival time of the patients with glioblastomas is less than 15 months.

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Background: Human gliomas are aggressive brain tumors characterized by uncontrolled cell proliferation. Differential expression of Polycomb repressive complex 2 (PRC2) has been reported in various subtypes of glioma. However, the role of PRC2 in uncontrolled growth in glioma and its underlying molecular mechanisms remain to be elucidated.

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Background: Since the long-term outcomes of 162 patients who underwent gamma knife radiosurgery (GKS) as an initial or adjuvant treatment for acoustic neuromas (ANs) with unilateral hearing loss were first reported in 1998, there has been no report of a comprehensive analysis of what has changed in GKS practice.

Methods: We performed a retrospective study of the long-term outcomes of 106 patients with unilateral sporadic ANs who underwent GKS as an initial treatment. The mean patient age was 50 years, and the mean initial tumor volume was 3.

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We present the clinicopathological and molecular genetic characteristics of a neuroepithelial tumor (NET), EWSR1::PATZ1 fusion-positive with a literature review. This fusion has recently been discovered in rare central nervous system tumors and soft tissue sarcomas and was not included in the fifth edition of the WHO classifications. We identified this fusion in 2 NETs.

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Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with poor prognosis and limited treatment options. While 5-fluorouracil (5-FU) has not been widely employed in GBM therapy, emerging research indicates its potential for effectiveness when combined with advanced drug delivery systems to improve its transport to brain tumors. This study aims to investigate the role of THOC2 expression in 5-FU resistance in GBM cell lines.

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Tumor spheroids are powerful tools for drug screening and understanding tumor physiology. Among spheroid formation methods, the hanging drop method is considered most suitable for high-throughput screening (HTS) of anticancer drugs because it does not require surface treatment. However, it still needs to increase the liquid-holding capacity because hanging drops often fall due to the increased pressure caused by the addition of drugs, cells, etc.

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Currently, research on superparamagnetic iron oxide nanoparticles (SPIONs) for magnetic hyperthermia applications is steadily increasing. In this work, SPIONs were synthesized by the bromide-assisted polyol method and angle-shaped SPIONs were successfully generated with the optimized concentration of bromide. The influence of bromide concentration on the shape of the generated SPIONs as well as the heating characteristics under an alternating magnetic field (AMF) was thoroughly investigated.

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