The recent recognition of human epidermal growth factor receptor 2 (HER2)–low and HER2-ultralow breast cancers (BCs) has expanded the therapeutic relevance of HER2 testing in the antibody-drug conjugate era. However, the biological continuum of HER2 expression measured by immunohistochemistry (IHC) and its relationship with the HER2 gene copy number remain unclear. Methods: We retrospectively analyzed 135 HER2-negative invasive BCs and reclassified them as HER2-null (IHC 0), HER2-ultralow (0+), or HER2-low (1+ or 2+ without amplification). HER2 gene copy number was determined using silver-enhanced in situ hybridization. Statistical analyses were performed to compare HER2 copy number among IHC categories and evaluate the discriminatory value of HER2 copy number for distinguishing IHC subgroups. Results: The mean HER2 copy number increased stepwise across IHC categories: 1.95 ± 0.54 (null), 2.03 ± 0.43 (ultralow), 2.25 ± 0.65 (low, 1+), and 3.29 ± 1.05 (low, 2+). Significant differences were observed between the ultralow and low groups (p = .003) and between the null and low groups (p < .001), but not between the null and ultralow groups or between the ultralow and 1+ groups. Conclusions: HER2 gene copy number was positively correlated with protein expression as reflected by IHC categories. Although HER2 gene copy number was statistically higher in HER2-low than in HER2-null tumors, the substantial overlap in copy number ranges likely limits its utility in distinguishing HER2-low from HER2- null BCs.

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.

Purpose: Chronic myeloid leukemia (CML) in children, adolescents, and young adults is rare and differs from older adults. This study evaluated the outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) in young Korean CML patients during the tyrosine kinase inhibitor (TKI) era. Materials and Methods: A retrospective analysis of 35 CML patients aged < 40 years who underwent allogeneic HSCT from 2009 to 2019 was conducted using Korean Blood and Marrow Transplantation Registry data. Patients were grouped by age < 20 years at HSCT (group 1, n=15) and 20-40 years at HSCT (group 2, n=20). Survival outcomes including overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS) were analyzed using the Kaplan-Meier method. Results: The median time between diagnosis and HSCT was 8.9 months. All the patients achieved engraftment but platelet recovery was significantly slower in group 1 (p=0.034). Acute and chronic graft-versus-host disease occurred in 54.3% and 34.3%, respectively. Five-year OS, RFS, and EFS rates of total patients were 66.8%, 50.8%, and 47.6%, with better OS was observed in group 1 by multivariable analysis (p=0.048). Disease status at HSCT was a significant predictor of OS (p=0.028), RFS (p=0.003), and EFS (p=0.004). Disease progression occurred in 13 out of 35 patients (37.1%); treatment-related mortality accounted for 63.6% of deaths (7 out of 11). Conclusion When performed at a younger age, allogeneic HSCT result in superior outcome in CML. Achieving remission before HSCT is critical for improved outcomes, highlighting the importance of pretransplant remission via optimal TKI strategies and minimal residual disease monitoring.

In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.

Purpose: The nutrient intake status of the groups classified by smoking amount, drinking frequency, and obesity were compared using data from the Eighth (2019) Korea National Health and Nutrition Examination Survey to examine the relationship of nutrient intake status with heath behavior in adults. Methods: This study analyzed the nutritional intakes of 4,379 people over 19-years old and compared nutrient intake amount (NIA) and density (ND), and ratios of nutrient intake (%DRI) and subjects intaking less (< DRI) compared to the daily dietary reference of the groups divided by health behaviors including smoking amount, drinking frequency, and obesity status. Results: NIA of dietary fiber, vitamin A, folic acid and vitamin C was lower in smoker groups compared to non-smoker group and ND of those decreased with smoking amount.%DRI of dietary fiber and vitamin C was also lower and < DRI of those higher in smoker group. NIA and ND of dietary fiber and vitamin C, and %DRI also decreased with drinking frequency. NIA of energy, protein, saturated fatty acid, iron, thiamin, and niacin was the highest in overweight group by body mass index (BMI), NIA of fat and sodium increased with obesity by BMI, and only sodium was higher in obese group by waist circumference. Lower consumption of dietary fiber and vitamin C in the groups of higher smoking amount and drinking frequency, and higher consumption of fat and sodium in obese groups imply the dietary problem to be improved. Conclusion This result implies that the nutritional status of the groups of smoking, drinking, or obesity have been improved but more effort is required to sustain the health diet at the same time.

Purpose: The nutrient intake status of the groups classified by smoking amount, drinking frequency, and obesity were compared using data from the Eighth (2019) Korea National Health and Nutrition Examination Survey to examine the relationship of nutrient intake status with heath behavior in adults. Methods: This study analyzed the nutritional intakes of 4,379 people over 19-years old and compared nutrient intake amount (NIA) and density (ND), and ratios of nutrient intake (%DRI) and subjects intaking less (< DRI) compared to the daily dietary reference of the groups divided by health behaviors including smoking amount, drinking frequency, and obesity status. Results: NIA of dietary fiber, vitamin A, folic acid and vitamin C was lower in smoker groups compared to non-smoker group and ND of those decreased with smoking amount.%DRI of dietary fiber and vitamin C was also lower and < DRI of those higher in smoker group. NIA and ND of dietary fiber and vitamin C, and %DRI also decreased with drinking frequency. NIA of energy, protein, saturated fatty acid, iron, thiamin, and niacin was the highest in overweight group by body mass index (BMI), NIA of fat and sodium increased with obesity by BMI, and only sodium was higher in obese group by waist circumference. Lower consumption of dietary fiber and vitamin C in the groups of higher smoking amount and drinking frequency, and higher consumption of fat and sodium in obese groups imply the dietary problem to be improved. Conclusion This result implies that the nutritional status of the groups of smoking, drinking, or obesity have been improved but more effort is required to sustain the health diet at the same time.

Purpose: The nutrient intake status of the groups classified by smoking amount, drinking frequency, and obesity were compared using data from the Eighth (2019) Korea National Health and Nutrition Examination Survey to examine the relationship of nutrient intake status with heath behavior in adults. Methods: This study analyzed the nutritional intakes of 4,379 people over 19-years old and compared nutrient intake amount (NIA) and density (ND), and ratios of nutrient intake (%DRI) and subjects intaking less (< DRI) compared to the daily dietary reference of the groups divided by health behaviors including smoking amount, drinking frequency, and obesity status. Results: NIA of dietary fiber, vitamin A, folic acid and vitamin C was lower in smoker groups compared to non-smoker group and ND of those decreased with smoking amount.%DRI of dietary fiber and vitamin C was also lower and < DRI of those higher in smoker group. NIA and ND of dietary fiber and vitamin C, and %DRI also decreased with drinking frequency. NIA of energy, protein, saturated fatty acid, iron, thiamin, and niacin was the highest in overweight group by body mass index (BMI), NIA of fat and sodium increased with obesity by BMI, and only sodium was higher in obese group by waist circumference. Lower consumption of dietary fiber and vitamin C in the groups of higher smoking amount and drinking frequency, and higher consumption of fat and sodium in obese groups imply the dietary problem to be improved. Conclusion This result implies that the nutritional status of the groups of smoking, drinking, or obesity have been improved but more effort is required to sustain the health diet at the same time.