Purpose: Although gastric cancer (GC) exhibits significant genomic heterogeneity, the clinical implications of its immune microenvironment remain poorly understood. Materials and Methods: We retrospectively evaluated patients with GC who underwent gastrectomies between 2011 and 2014. The tumors were analyzed for Epstein–Barr virus (EBV), microsatellite instability-high (MSI-H), tumor-infiltrating lymphocytes (CD3), tumor-associated macrophages (CD68 and CD163), and programmed death-ligand 1 (PD-L1) expression. Tumors were classified using the modified The Cancer Genome Atlas scheme, and their clinical characteristics were compared. Results: A total of 567 patients were classified into EBV (6%), MSI-H (10%), chromosomal instability-like (36%), and genomically stable-like (48%) subtypes. EBV tumors exhibited the highest PD-L1 expression (85%) and immune infiltration by CD3+ T cells (86%), CD68+ macrophages (58%), and CD163+ macrophages (40%). High CD68+ macrophage tumors were associated with advanced stages and worse 5-year disease-free survival (83% vs. 95%; P<0.001);however, this association was not independently significant after adjusting for the tumor-nodemetastasis stage. PD-L1 expression did not significantly affect the survival outcomes. Conclusions GC subtypes have distinct immune microenvironments that influence prognosis. Our findings highlight the prognostic and therapeutic potential of immune profiling in GC.

Purpose: Endoscopic submucosal dissection (ESD) has become a standard minimally invasive treatment for selected patients with early gastric cancer (EGC). This study presents the first nationwide survey of patients with EGC treated with ESD in 2023, conducted by the Korean College of Helicobacter and Upper Gastrointestinal Research. Materials and Methods: Data were retrospectively collected from participating referral centers across Korea using a standardized case report form covering patient characteristics, tumor features, procedural details, histopathological findings, and clinical outcomes.Descriptive and comparative analyses were conducted to summarize nationwide ESD practice patterns and outcomes. Results: Data from 5,460 ESD cases from 5,250 patients across 27 institutions were analyzed. The mean age was 67.4 years, with 74.1% males. Multiple synchronous lesions were identified in 3.7%. Most lesions were located in the lower third of the stomach (64.0%), and differentiated-type adenocarcinomas accounted for 87.8%. The en bloc and complete resection rates were 99.2% and 91.4%, respectively. Curative resection was achieved in 80.5%, whereas local non-curative resection (L-NCR) and surgical non-curative resection (S-NCR) were identified in 2.8% and 16.7%, respectively. Additional surgery was performed more frequently in patients with S-NCR than in those with L-NCR (59.3% vs. 24.7%). The bleeding and perforation rates were 3.6% and 0.9%, respectively, and were mostly managed conservatively or endoscopically. The median length of hospitalization was 4.0 days. Conclusions This first nationwide survey provides a comprehensive overview of the current practice of EGC treatment using ESD in Korea, demonstrating high technical success and safety, and establishing a baseline dataset for future longitudinal research.

This study aims to present the surgical technique and clinical outcomes of reduced-port robotic extended cholecystectomy using the da Vinci Single Port (SP) system (Intuitive Surgical) in a patient diagnosed with gallbladder cancer. The da Vinci SP surgical system was employed to perform a reduced-port robotic extended cholecystectomy in a patient with gallbladder cancer. Procedural details, operative time, estimated blood loss, and postoperative outcomes were documented and analyzed. The total operative time was 210 minutes, with an estimated blood loss of less than 400 mL. No intraoperative complications were reported. The patient had an uneventful recovery and was discharged on postoperative day 8. The da Vinci SP system appears to be a safe and feasible platform for performing reduced-port robotic extended cholecystectomy, with acceptable perioperative outcomes in appropriately selected patients.

This study aimed to determine the prevalence of human epidermal growth factor receptor 2 (HER2)–ultralow breast cancer among cases initially classified as HER2 immunohistochemistry (IHC) 0 and assess interobserver variability in interpreting low-level HER2 expression. Methods: In this multicenter retrospective study, all invasive breast cancer cases diagnosed between January and December 2022 across 10 Korean institutions were retrieved. Institutional pathologists reexamined HER2 IHC slides originally reported as IHC 0 according to the 2018 American Society of Clinical Oncology/College of American Pathologists guidelines and reclassified them as HER2-null (0), HER2-ultralow (0+), or HER2-low (1+). Slides from 10% of HER2-null and HER2-ultralow cases were digitized for central review and independently assessed by two pathologists, with discrepancies resolved by consensus. Results: Among 8,026 cases, 2,836 cases (35.5%) were initially reported as IHC 0. Upon re-review, 1,673 (59.0%), 1,139 (40.2%), and 24 (0.8%) cases were reclassified as HER2-null, HER2-ultralow, and HER2-low, respectively. The prevalence of HER2-ultralow breast cancer varied considerably across institutions (23.7%–78.1%). Central review of 268 digitized cases showed concordance in 193 cases (72.0%). Among the 75 discordant cases, 54 tumors (72.0%) were upgraded from HER2-null to HER2-ultralow, and 18 (24.0%) tumors were upgraded from HER2-ultralow to HER2-low. Furthermore, two tumors (2.7%) were downgraded from HER2-ultralow to HER2-null. Conclusions: Approximately 40% of cases initially categorized as IHC 0 were reclassified as HER2-ultralow. The substantial inter-institutional variability observed in interpreting low-level HER2 expression highlights the need for standardized training and quality assurance to ensure accurate identification of patients eligible for HER2-targeted antibody–drug conjugates.

Coronary CT-derived fractional flow reserve (CT-FFR) is a noninvasive alternative to invasive FFR for assessing the hemodynamic significance of coronary artery stenosis. CT-FFR uses routinely acquired coronary CT angiography (CCTA) with artificial intelligence and computational fluid dynamics to estimate pressure gradients, thereby supporting clinical decisionmaking without procedural risk. Adoption and implementation vary widely across regions. In Asia, South Korea exclusively uses HeartMedi+, which enables rapid analysis, streamlined workflow integration, and high user satisfaction. Japan relies primarily on FFR CT, which has national reimbursement and significantly influences treatment strategies, reducing unnecessary invasive procedures. Hong Kong, Singapore, Taiwan, Thailand, and Vietnam remain in early or exploratory phases due to cost, reimbursement, and infrastructure barriers. In the United States, CT-FFR is guideline-endorsed and reimbursed, where HeartFlow is the most widely used, supported by robust clinical validation and outcome data. Despite regional variability, CTFFR offers a noninvasive solution that enhances patient management, reduces unnecessary invasive testing, and is poised for broader clinical integration as technology and validation advance.

Background: In the era of nucleoside analogs (NA), we investigated the safety of using hepatitis B surface antigen (HBsAg)-positive grafts in liver transplantation (LT) using nationwide KOTRY data. Methods: Among 4,265 adult LTs in the KOTRY registry (April 2014–January 2020), 20 (0.5%) used HBsAg(+) grafts. The S(+) group was compared with HBsAg-nega-tive groups, both HBcAb(+) (C[+]) and HBcAb(−) (SC[−]), using 1:1 propensity scorematching. Patient and graft survival were evaluated using Kaplan–Meier analysis.Cox regression was used to identify prognostic factors. Results: No significant differences were observed in patient or graft survival be-tween S(+) and C(+) or SC(−) groups. Key prognostic factors for patient survivalincluded age, HCC, MELD score, ascites, and encephalopathy. For graft survival, HCC, preoperative HCC treatment, MELD score, ascites, and encephalopathy were significant. HBV recurrence occurred in the S(+) group, but did not compromise outcomes. Conclusion In HBV-endemic regions, HBsAg(+) liver grafts can be safely used to expand the donor pool without compromising LT outcomes when combined with appropriate prophylaxis.

Purpose: This study aimed to report the real-world outcomes of intravesical gemcitabine for bacillus Calmette–Guérin (BCG)–unresponsive, high-risk, non–muscle-invasive bladder cancer (HR-NMIBC) in Korean patients who were unable or unwilling to undergo radical cystectomy (RC). Materials and Methods: This retrospective study included 131 patients (median age, 69 years; 88.5% men) treated with intravesical gemcitabine for BCG-unresponsive HR-NMIBC at nine centers between May 2019 and April 2022. The primary endpoint was 1-year recurrence-free survival (RFS). The secondary endpoints included factors influencing RFS, progression-free survival (PFS), cystectomy- free survival, cancer-specific survival (CSS), overall survival (OS), and safety. Survival analysis was performed using the Kaplan-Meier method, and risk factors for recurrence were assessed using Cox regression models. Results: Patients were followed up for a median duration of 25 months, with carcinoma in situ (CIS) in 41.9% of the patients. The 1-year and 2-year RFS rates were 68% and 42%, while the 1-year and 2-year PFS rates were 87% and 77%, respectively. No significant factors influencing RFS were identified. Seventeen patients underwent RC during a median follow-up of 16 months, with the condition in three patients progressing to muscle-invasive disease on final pathological analysis. The 2-year CSS and OS rates were 98% and 97%, respectively. Intravesical gemcitabine was well-tolerated, with only seven patients (5.3%) unable to complete the full induction course. Conclusion Our research highlights the potential of intravesical gemcitabine as a viable bladder-sparing treatment option for BCG-unresponsive HR-NMIBC, providing real-world evidence on its safety, efficacy, and tolerability.

Purpose: Ovarian cancer presents significant treatment challenges due to its aggressive nature and poor response to immune checkpoint inhibitors (ICIs). The lack of standardized programmed cell death-ligand 1 (PD-L1) assays and cut-off values complicates clinical decision-making. We evaluated the concordance among commonly used PD-L1 assays and assessed changes in the expression of PD-L1 following chemotherapy. Materials and Methods: Tissue samples from 29 patients with ovarian cancer were analyzed using five validated PD-L1 immunohistochemistry assays: Dako 22C3, Ventana SP263, Ventana SP142, Dako 28-8, and Ventana 22C3. PD-L1 positivity was assessed using a combined positive score (CPS), immune cell, or tumor proportion score at 1%, 5%, and 10% cut-offs. Concordance rates, including overall percent agreement and Cohen’s kappa coefficient, were analyzed. In addition, changes in the expression of PD-L1 pre- and postchemotherapy were evaluated. Results: Positivity rates ranged from 15.8% (SP142) to 29.8% (Dako 22C3 and SP263) at the 1% CPS cut-off. SP142 consistently exhibited the lowest concordance, whereas Dako 22C3 displayed high agreement with SP263, 28-8, and Ventana 22C3. Chemotherapy increased PD-L1 positivity, with 28% of patients converting from negative to positive. Conclusion The expression of PD-L1 in ovarian cancer varies across assays and scoring methods, emphasizing the need for standardized testing protocols. Increased PD-L1 expression post-chemotherapy underscores the importance of assessing its status at appropriate times to guide ICI therapy. Larger studies are required to validate these findings and refine clinical applications.

The COVID-19 pandemic has adversely affected the mental health of the global population. This study aimed to assess the acute and persistent symptoms of depression, as well as factors related to their manifestation, through a longitudinal study design. A total of 1,492 community-dwelling adults from an online public panel across three regions were evaluated at baseline, with 908 adults (60.9%) followed up after six months. Depression symptoms were evaluated using Patient Health Questionnaire-9 (PHQ-9). Participants also completed self-administered questionnaires on sociodemographic information, psychosocial experiences related to COVID-19, the UCLA Loneliness Scale, and the Korean version of the Gratitude Questionnaire (K-GQ-6).The prevalence of acute and persistent depression symptoms was 8.4% and 12.0%, respectively. Multivariate logistic regression analysis identified changes in predictors of depression over time, with younger age and self-isolation experience found to be associated with acute depression. Factors such as underlying mental illness, eating and sleeping disturbances, loneliness, and COVID-19-related stress emerged as significant risk factors for persistent depression. A disposition toward gratitude was identified as a protective factor for persistent depressive symptoms. These findings suggest that during any long-term pandemic crisis such as COVID-19, timely support and attention are essential for vulnerable populations, including young people and individuals with mental health conditions, to prevent depression. Specifically, promoting daily routines such as regular eating and sleeping patterns, and managing COVID-19-related stress may be critical in preventing persistent depression. Additionally, psychological support that reduces loneliness and fosters gratitude may help mitigate depression risk.

Objectives: This study aimed to investigate the impact of behavioral and psychological symptoms (BPS), assessed by the neuropsychiatric inventory (NPI) total score, on instrumental activities of daily living (IADL) performance in patients with mild cognitive impairment. Methods: Ninety-two patients diagnosed with mild cognitive impairment who visited a university hospital dementia clinic were recruited. Assessments included the Korean version-Mini Mental State Examination, NPI, Korean-IADL (KIADL), and Short Form of Geriatric Depression Scale-Korean version. Correlation and hierarchical multiple regression analyses were performed to analyze the relationship between BPS and IADL. Results: The mean age of participants was 74.61±5.86 years. K-IADL scores significantly correlated with age (r=0.347, p<0.001) and NPI total score (r=0.265, p<0.05). Hierarchical regression analysis showed that the addition of the NPI total score significantly increased the explained variance of functional decline (R 2 =0.197, F=5.332, p<0.001), with age (β=0.354, p<0.001) and NPI total score (β=0.248, p<0.05) identified as independent predictors in patients with mild cognitive impairment. Conclusions The overall severity of BPS exerts a detrimental effect on IADL function in mild cognitive impairment patients, independent of age and cognitive status. These results underscore the clinical importance of evaluating the cumulative burden of BPS to predict functional prognosis and implement early interventions.