1.Transformation of Pleomorphic Xanthoastrocytoma with Germline ATM Mutation into a SMARCB1-Deficient Rhabdoid Tumor: A Case Report
Hyeonseung LEE ; Hyun Jin PARK ; Bo Kyung KIM ; Kyung Taek HONG ; Hyoung Jin KANG ; Sung-Hye PARK ; Ji Hoon PHI ; June-Young KOH ; Jung Yoon CHOI
Clinical Pediatric Hematology-Oncology 2026;33(1):34-38
Secondary rhabdoid tumors (RTs) with atypical teratoid/rhabdoid tumor-like features rarely arise from, or coexist with, pleomorphic xanthoastrocytomas (PXAs), and their clinicopathological and molecular characteristics remain poorly understood. We report a 17-year-old girl with a temporal lobe mass that, upon gross total resection, pathologically contained both RT and PXA components. Immunohistochemistry revealed loss of INI1 expression restricted to the RT component, while the PXA area retained INI1. Next-generation sequencing identified a shared BRAF::TRIM24 fusion and homozygous deletion of CDKN2A/2B in both components, indicating a shared clonal origin. Additionally, a germline ATM frameshift mutation (c.5288_5289insGA) was identified in both tumor components, making the first such report in central nervous system tumors. SMARCB1 loss was confined to the RT component, further supporting the hypotheses of clonal evolution and secondary transformation. Despite gross total resection, craniospinal irradiation, and chemotherapy, the patient developed rapid leptomeningeal dissemination and died 5 months after surgery. This case provides clinicopathological and molecular evidence for clonal evolution and secondary transformation of PXA into an RT. The presence of germline ATM mutation may have therapeutic and biological relevance. Further studies are required to clarify the pathogenesis and optimal management of these rare and aggressive tumors.
2.Exploring the Association Between Physical Fitness Components and Cognitive Function in Older Korean Adults: The SUPERBRAIN Exploratory Sub-study
Da Ae KIM ; Buongo CHUN ; Muncheong CHOI ; Kyunghwa SUN ; Jee Hyang JEONG ; Yoo Kyoung PARK ; Chang Hyung HONG ; Hae Ri NA ; Seong Hye CHOI ; So Young MOON ; Hong-sun SONG ; Sun Min LEE
Dementia and Neurocognitive Disorders 2026;25(1):13-24
Background:
and Purpose: Tailored physical exercise interventions have the potential to promote cognitive health in older adults and offer significant advantages for those more vulnerable to decline. The specific relationship between physical fitness and cognition among the elderly has not been clearly established. The purpose of this investigation was to assess the relationship between physical fitness and cognitive function in older Korean adults.
Methods:
Eighty-four community-dwelling older adults (mean age: 70.7±5.3 years; 81.0% female) completed a standardized physical fitness battery assessing handgrip strength, sit-and-reach, 30-second sit-to-stand, 2-minute stationary march, 3-m sit-walk-and-return, figure-8-walk, and T-wall response time. Cognitive function was evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Descriptive statistics, partial correlation analyses, and stepwise multiple linear regression were conducted.
Results:
Slower T-wall response time was significantly correlated with lower RBANS total index, immediate memory, and delayed memory scores. In regression models, slower T-wall response time was independently associated with lower RBANS total index (β=−0.234, p=0.026) and delayed memory scores (β=−0.295, p=0.029). The regression model for immediate memory was not statistically significant overall; therefore, no predictive conclusion was drawn for this domain. Higher education showed a significant positive association with cognitive performance.
Conclusions
Coordination, as measured by T-wall response time, emerged as the only physical fitness component consistently associated with cognitive performance in older adults. Coordination-related fitness may be an important correlate of cognitive function in older adults and a promising target for future exercise interventions.
3.Enavogliflozin, an SGLT2 Inhibitor, Improves Nonalcoholic Steatohepatitis Induced by High-Fat, High-Cholesterol Diet
Phuc Thi Minh PHAM ; Giang NGUYEN ; So Young PARK ; Thuy Linh LAI ; Dae-Hee CHOI ; Jeana HONG ; Seon Mee KANG ; Eun-Hee CHO
Diabetes & Metabolism Journal 2026;50(1):165-177
Background:
Nonalcoholic fatty liver disease, a progressive condition caused by the accumulation of fat in the liver, begins with simple steatosis and can potentially progress to metabolic dysfunction-associated steatohepatitis (MASH) in the presence of inflammation and fibrosis, ultimately leading to cirrhosis or hepatocellular carcinoma. Increasing evidence indicates that sodiumglucose cotransporter 2 (SGLT2) inhibitors effectively alleviate MASH in mouse models. However, there is a lack of research on the effects of enavogliflozin on liver disease. In the present study, we investigated the effects of SGLT2 inhibitors on MASH induced by a high-fat, high-cholesterol (HFHC) diet in mice.
Methods:
Male C57BL/6 mice were fed a normal chow diet, HFHC diet, or HFHC diet with enavogliflozin for 12 weeks. LX-2 and HepG2 cells were treated with enavogliflozin in the presence of various pathological stimuli.
Results:
The HFHC diet induced excessive hepatic lipid accumulation, inflammation, and severe fibrosis. Administration of enavogliflozin not only ameliorated hepatic steatosis and fibrotic conditions but also suppressed the production of inflammatory cytokines. Positive outcomes were also observed in in vitro experiments, where enavogliflozin demonstrated the ability to impede the activation of hepatic stellate cells and alleviate lipid accumulation in hepatocytes. The potential pathway through which enavogliflozin attenuated liver fibrosis development may be associated with the transforming growth factor β1/Smad signaling pathway.
Conclusion
Our results suggest that enavogliflozin is effective in a mouse model of MASH by attenuating hepatic steatosis, suppressing inflammation, and improving liver fibrosis.
4.Structured Integration of an Artificial Intelligence-Based System for the Optical Diagnosis of Colorectal Polyps
Hae Yeon KANG ; Soonwhan KANG ; Goh Eun CHUNG ; Dong Hoon BAEK ; Hong Sub LEE ; Jinbae PARK ; Sun Young YANG ; Seon Hee LIM ; Ji Min CHOI ; Jung KIM ; Jung Ho BAE
Gut and Liver 2026;20(1):86-96
Background/Aims:
Recent advances in computer-aided diagnosis (CADx) systems have demonstrated expert-level accuracy in the optical diagnosis of colorectal polyps. High-confidence (HC) diagnoses have been defined as those made within 3 seconds without hesitation, and these systems have been shown to improve diagnostic accuracy. We aimed to evaluate the performance of endoscopists with varying levels of experience in diagnosing colorectal polyps with the assistance of a new CADx system applying the 3-second rule and without artificial intelligence assistance.
Methods:
In this multicenter ex vivo study, 35 endoscopists assessed 100 polyps (51 adenomas, 39 hyperplastic polyps, 10 sessile serrated lesions) using narrow-band imaging video clips on an online platform. Assessments consisted of individual endoscopist diagnosis and CADx-assisted diagnosis. HC assignments followed the 3-second rule in both phases. Performance metrics included HC accuracy, HC rate, and adherence to the Preservation and Incorporation of Valuable Endoscopic Innovations (PIVI) and Simple Optical Diagnosis Accuracy (SODA) thresholds.
Results:
HC diagnostic accuracy improved from 78.3% (95% confidence interval [CI], 76.6% to 80.0%) to 89.8% (95% CI, 88.6% to 90.9%) with CADx assistance (p<0.001). The proportion of HC predictions increased from 64.2% to 75.4% (p<0.001). Novice endoscopists showed marked improvement with CADx (74.1% vs 88.8%; p<0.001). CADx-assisted diagnoses nearly met SODA and PIVI thresholds under the 3-second rule. Additional analysis demonstrated that CADx assistance significantly improved interobserver agreement and ground truth, particularly for novices (κ=0.37 to κ=0.65; p<0.001).
Conclusions
Integrating CADx with the 3-second rule significantly enhances the performance of endoscopists in the optical diagnosis of colorectal polyps, with the greatest benefit observed among novice endoscopists.
5.Optimal use and cycling strategies of Janus kinase inhibitors in ulcerative colitis: current evidence and clinical implications from the KASID Guidelines Task Force Team
Seung Min HONG ; Dong Hyun KIM ; June Hwa BAE ; Seung Yong SHIN ; Eun Mi SONG ; Ji Eun KIM ; Young Joo YANG ; Jiyoung YOON ; Sang-Bum KANG ; Eun Soo KIM ; Seong-Eun KIM ; Seong-Jung KIM ; Jun LEE ; Soo-Young NA ; Soo Jung PARK ; Sang Hyoung PARK ; Miyoung CHOI ; Myung Ha KIM ; Won MOON ; Sung-Ae JUNG ;
Intestinal Research 2026;24(1):27-37
Janus kinase (JAK) inhibitors are an important treatment option for ulcerative colitis, providing rapid onset of action, oral administration, and efficacy even after biologic failure. The 3 approved agents—tofacitinib, filgotinib, and upadacitinib—differ in JAK isoform selectivity, leading to clinically meaningful differences in efficacy and safety. Evidence from network meta-analyses, clinical trials, and real-world studies consistently shows that upadacitinib provides the highest efficacy for induction and maintenance of remission, whereas filgotinib demonstrates the most favorable safety profile. The strong efficacy of upadacitinib and tofacitinib is particularly relevant in patients with severe disease, including acute severe ulcerative colitis, and upadacitinib maintains high efficacy regardless of prior advanced therapy exposure. JAK inhibitors also benefit extraintestinal manifestations. Although risks such as herpes zoster, serious infection, thromboembolism, and major cardiovascular events differ among agents, long-term data suggest generally acceptable safety when used appropriately. Intraclass JAK-to-JAK cycling is feasible, with about half of patients achieving steroid-free clinical remission in retrospective cohorts. Based on mechanistic, clinical, and real-world evidence, filgotinib may be a first-line option for patients with lower disease activity or when safety is a priority, whereas upadacitinib or tofacitinib may be preferred in higher disease activity. Strategically selecting agents may improve durability and outcomes.
6.Divergent Propagation Networks Define Two Pathophysiologically Distinct Electroclinical Phenotypes in Mesial Temporal Lobe Epilepsy
Heewon BAE ; Dae Won SEO ; Seung Bong HONG ; Hea Ree PARK ; Young-Min SHON
Journal of Clinical Neurology 2026;22(2):203-211
Background:
and Purpose Temporal dissociation between electrographic and clinical seizure onset in mesial temporal lobe epilepsy (MTLE) implies network heterogeneity. We hypothesized that MTLE consists of distinct electroclinical phenotypes defined by divergent seizure propagation dynamics.
Methods:
We retrospectively analyzed 167 seizures from 13 patients with drug-resistant MTLE who achieved Engel Class I surgical outcomes. Based on the predominant relationship between scalp electroencephalography (EEG) and clinical onset, patients were classified as EEG-first (n=7) or Clinical-first (n=6). Seizure onset patterns, propagation pathways, and temporal dynamics were assessed using scalp and stereoelectroencephalography (SEEG).
Results:
The cohort included 83 scalp and 84 SEEG seizures. By definition, onset order differed: in EEG-first seizures, scalp changes preceded clinical signs in 70.5%, whereas the reverse occurred in 65.8% of Clinical-first seizures (p<0.001). EEG-first seizures demonstrated longer SEEG-to-clinical latency (28.8±7.7 s vs. 13.0±7.7 s; p=0.004) and rhythmic theta onset on scalp EEG with focal SEEG low-voltage fast activity or preictal spikes. In contrast, Clinical-first seizures showed heterogeneous scalp patterns (theta, delta–theta, or delta slowing). Propagation tended to differ, with anterior pathways more common in EEG-first (69.6%) and posterior pathways in Clinical-first (26.3%), though with partial overlap (p=0.138).
Conclusions
MTLE comprises two pathophysiologically distinct phenotypes: EEG-first, reflecting a slowly propagating anterior mesial network, and Clinical-first, involving a rapidly spreading posterior network. This classification offers a mechanistic framework for understanding electroclinical dissociation and may refine presurgical evaluation.
7.A Pilot Study on the Use of Topical Gold and Diamond Suspension Combined With 1,064 nm Picosecond Nd:YAG Laser for the Treatment of Facial Melasma
Ji Yeon HONG ; Hye Sung HAN ; Kui Young PARK
Annals of Dermatology 2026;38(1):27-32
Background:
Carbon suspension with laser irradiation was used for facial melasma, but it produces harmful fumes. Gold and diamond are biocompatible and chemically inert, and expected to act as potent chromophores and microdermabrasion agents, respectively.
Objective:
This study aimed to evaluate the efficacy and safety of microgold and microdiamond suspensions with a 1,064 nm picosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) laser for melasma.
Methods:
Ten Korean patients received 2 laser sessions using gold and diamond suspension at 2-week intervals. Melasma area severity index (MASI), melanin index (MI), erythema index (EI), Physician/Subject global aesthetic improvement scale (PGAIS/SGAIS), and adverse events were assessed at baseline, week 2 and week 4.
Results:
MASI and MI scores significantly improved. EI score showed no significant changes.All patients showed aesthetic improvement by PGAIS and SGAIS. No severe or unexpected adverse events were reported.
Conclusion
The topical microgold and microdiamond suspension combined with a 1,064 nm picosecond Nd:YAG laser appears to be a safe and effective treatment option for facial melasma.
8.Molecular Epidemiology of Extended-spectrum β-Lactamase-producing Escherichia coli in South Korea: A Korean Global Antimicrobial Resistance Surveillance System Report
Dokyun KIM ; SungYoung LEE ; Jun Sung HONG ; Min Hyuk CHOI ; Hyun Soo KIM ; Young Ree KIM ; Young Ah KIM ; Young UH ; Kyeong Seob SHIN ; Jeong Hwan SHIN ; Jeong Su PARK ; Kyoung Un PARK ; Soo Hyun KIM ; Jong Hee SHIN ; Jungsik YU ; Seok Hoon JEONG
Annals of Laboratory Medicine 2026;46(1):72-82
Background:
Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is among the most important multidrug-resistant pathogens causing bloodstream infections (BSIs).Cefotaximase (CTX-M) enzymes are the most common and highly diverse ESBL family in E.coli. CTX-M-15 in group CTX-M-1 and CTX-M-14 in group CTX-M-9 are the most extensively disseminated enzymes. Multidrug-resistant E. coli strains complicate empirical therapy and increase healthcare burden globally and in Korea. We investigated the molecular epidemiology, sequence types (STs), and ESBL genotypes of E. coli bloodstream isolates in Korea and identified clinical risk factors for cefotaxime resistance.
Methods:
We collected all non-duplicated isolates of E. coli and related clinical information from patients with BSIs at eight sentinel hospitals in the Korean Global Antimicrobial Resistance Surveillance System (Kor-GLASS) collection network during 2017–2021. Duplicate isolates were removed to ensure representativeness of the data. Antimicrobial susceptibility was tested using disk diffusion tests, and multilocus sequence typing and betalactamase genotyping were performed.
Results:
Among 9,232 E. coli blood isolates, resistance rates to cefotaxime and ceftazidime were 36.4% and 11.4%, respectively. Among the clinical factors, age > 65 yrs (adjusted odds ratio [aOR], 1.36), hospital-origin infection (aOR, 2.55), and admission type (intensive care unit [ICU] vs. general ward; aOR, 1.34) were significant cefotaxime resistance risk factors. ST131 was the most prevalent among cefotaxime-resistant E. coli (64.8%, 2,180/3,363), followed by ST1193 (5.3%, N = 177), and ST69 (5.1%, N = 170).ST131, ST648, ST405, and ST410 cefotaxime-resistant E. coli isolates frequently harbored blaCTX-M-15, whereas ST1193 and ST68 showed a high proportion of blaCTX-M-27 carriers, and most ST457 and ST5150 isolates carried blaCTX-M-55.
Conclusions
Continuous monitoring of ESBL-producing E. coli is required to prevent further dissemination, guide empirical therapy, inform infection control policies, and ensure early detection of multidrug-resistant clones with the potential for widespread transmission.
9.Applying National Whole-genome Sequencing Findings for Rare Diseases in Clinical Practice: The Imperative of a Multidisciplinary Approach
Kyung Sun PARK ; Sunghwan SHIN ; Jong-Ho PARK ; Young-Eun KIM ; Won Kyung KWON ; Min-Kyung SO ; Changhee HA ; Ja-Hyun JANG ; Taeheon LEE ; Chang-Seok KI ; Yoonjung KIM ; Kyung-A LEE ; Inho PARK ; Sejoon LEE ; Hong-Hee WON ; ; Jong-Won KIM
Annals of Laboratory Medicine 2026;46(1):94-103
Background:
As nationwide government-led whole-genome sequencing (WGS) projects progress, optimizing the clinical integration of large-scale WGS results is crucial. We explored how the initial analysis from Korea’s First WGS Pilot Study for Rare Diseases was applied in clinical practice, and then we reanalyzed the data comprehensively at Samsung Medical Center (SMC) Seoul, Korea.
Methods:
A prospective cohort study designed to collect WGS data under a Korean national initiative was conducted from August 2020 to December 2021. We focused on patients with rare diseases recruited from 16 university hospitals. The participants included 5,000 individuals (2,200 probands and 2,800 family members). The initial WGS data and diagnostic reference reports (from 682 probands and 484 family members), generated based on the First Korean WGS Pilot Study for Rare Diseases, were subsequently reanalyzed by SMC.
Results:
The initial analysis of the First Korean WGS Pilot Study data revealed a diagnostic rate of 17%. Upon receiving these results, the SMC conducted two rounds of reanalysis, increasing the diagnostic rate from 15% in the first analysis, to 18% in the second, and finally to 24% in the third (P = 1.6 × 10 −5 ). Key factors in improving the genetic diagnosis included increased detection of novel (likely) pathogenic variants (P = 1.0 × 10 −4 ), improved diagnostic rates with larger family recruitment (P = 0.004), and refined clinical information for more precise genotype–phenotype correlation analysis (40%).
Conclusions
Although national WGS projects lay a foundation for rare disease diagnosis, hospital-level reanalysis and multidisciplinary collaborations are crucial for optimizing diagnostic outcomes.
10.Unique TTR Variants D38A and M13dup Among Korean Patients with Hereditary Transthyretin Amyloidosis:A Retrospective Single-Center Cohort Study
Min-Seung PARK ; Jae Joon LEE ; Darae KIM ; Jin-Oh CHOI ; Seok Jin KIM ; Kihyun KIM ; Ju-Hong MIN ; Hyun-Young KIM ; Hee-Jin KIM
Annals of Laboratory Medicine 2026;46(3):309-318
Background:
Transthyretin amyloidosis, a protein-misfolding disorder characterized by systemic amyloid deposition, can be classified as wild-type transthyretin amyloidosis (ATTRwt) or hereditary transthyretin amyloidosis (ATTRv), depending on the presence of transthyretin (TTR) gene variants. We examined the genetic distribution of TTR variants in Korean patients diagnosed with ATTRv.
Methods:
We retrospectively reviewed 801 participants who underwent TTR analysis at Samsung Medical Center from 2012 to 2024. The participants were categorized into two groups: in-house probands or relatives, and externally referred probands or relatives.
Results:
Pathogenic or likely pathogenic TTR variants were detected in 36 of 165 in-house probands (21.8%), among which D38A was the most frequent variant (50.0%; 18/36), followed by M13dup and E89K (8.3% each). Among referred probands, D38A was predominant (54.5%; 12/22), followed by M13dup (22.7%; 5/22). Cardiac amyloid involvement was the most common manifestation, observed in 97.2% (35/36) of in-house probands with ATTRv, followed by peripheral nervous system (PNS; 94.4%) and autonomic nervous system (ANS; 88.9%) involvement. In contrast, ANS involvement was most prevalent among in-house relatives who underwent organ evaluation (61.5%; 24/39), followed by cardiac (52.1%; 25/48) and PNS (48.7%; 19/39) involvement. Five of the eight in-house relatives harboring M13dup (62.5%) showed organ involvement, primarily in the ANS, supporting the pathogenicity of this variant.
Conclusions
This study provides the largest single-institution dataset of Korean patients with ATTRv, incorporating systematic organ assessments. The predominance of the unique TTR variants D38A and M13dup delineates a distinct genetic landscape that may facilitate accurate and timely diagnosis of ATTRv in the Korean population.

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