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.

Children face the excitement of a changing world but also encounter environmental threats to their health that were neither known nor suspected several decades ago. Children are at particular risk of exposure to pollutants that are widely dispersed in the air, water, and food. Children and adolescents are exposed to chemical, physical, and biological risks at home, in school, and elsewhere. Actions are needed to reduce these risks for children exposed to a series of environmental hazards. Exposure to a number of persistent environmental pollutants including air pollutants, endocrine disruptors, noise, electromagnetic waves (EMWs), tobacco and other noxious substances, heavy metals, and microplastics, is linked to damage to the nervous and immune systems and affects reproductive function and development. Exposure to environmental hazards is responsible for several acute and chronic diseases that have replaced infectious diseases as the principal cause of illnesses and death during childhood. Children are disproportionately exposed to environmental toxicities. Children drink more water, eat more food, and breathe more frequently than adults. As a result, children have a substantially heavier exposure to toxins present in water, food, or air than adults. In addition, their hand-to-mouth behaviors and the fact that they live and play close to the ground make them more vulnerable than adults. Children undergo rapid growth and development processes that are easily disrupted. These systems are very delicate and cannot adequately repair thetional development in children’s environmental health was the Declaration of the Environment Leaders of the Eight on Children’s Environmental Health by the Group of Eight. In 2002, the World Health Organization launched an initiative to improve children’s environmental protection effort. Here, we review major environmental pollutants and related hazards among children and adolescents.

Children face the excitement of a changing world but also encounter environmental threats to their health that were neither known nor suspected several decades ago. Children are at particular risk of exposure to pollutants that are widely dispersed in the air, water, and food. Children and adolescents are exposed to chemical, physical, and biological risks at home, in school, and elsewhere. Actions are needed to reduce these risks for children exposed to a series of environmental hazards. Exposure to a number of persistent environmental pollutants including air pollutants, endocrine disruptors, noise, electromagnetic waves (EMWs), tobacco and other noxious substances, heavy metals, and microplastics, is linked to damage to the nervous and immune systems and affects reproductive function and development. Exposure to environmental hazards is responsible for several acute and chronic diseases that have replaced infectious diseases as the principal cause of illnesses and death during childhood. Children are disproportionately exposed to environmental toxicities. Children drink more water, eat more food, and breathe more frequently than adults. As a result, children have a substantially heavier exposure to toxins present in water, food, or air than adults. In addition, their hand-to-mouth behaviors and the fact that they live and play close to the ground make them more vulnerable than adults. Children undergo rapid growth and development processes that are easily disrupted. These systems are very delicate and cannot adequately repair thetional development in children’s environmental health was the Declaration of the Environment Leaders of the Eight on Children’s Environmental Health by the Group of Eight. In 2002, the World Health Organization launched an initiative to improve children’s environmental protection effort. Here, we review major environmental pollutants and related hazards among children and adolescents.

Children face the excitement of a changing world but also encounter environmental threats to their health that were neither known nor suspected several decades ago. Children are at particular risk of exposure to pollutants that are widely dispersed in the air, water, and food. Children and adolescents are exposed to chemical, physical, and biological risks at home, in school, and elsewhere. Actions are needed to reduce these risks for children exposed to a series of environmental hazards. Exposure to a number of persistent environmental pollutants including air pollutants, endocrine disruptors, noise, electromagnetic waves (EMWs), tobacco and other noxious substances, heavy metals, and microplastics, is linked to damage to the nervous and immune systems and affects reproductive function and development. Exposure to environmental hazards is responsible for several acute and chronic diseases that have replaced infectious diseases as the principal cause of illnesses and death during childhood. Children are disproportionately exposed to environmental toxicities. Children drink more water, eat more food, and breathe more frequently than adults. As a result, children have a substantially heavier exposure to toxins present in water, food, or air than adults. In addition, their hand-to-mouth behaviors and the fact that they live and play close to the ground make them more vulnerable than adults. Children undergo rapid growth and development processes that are easily disrupted. These systems are very delicate and cannot adequately repair thetional development in children’s environmental health was the Declaration of the Environment Leaders of the Eight on Children’s Environmental Health by the Group of Eight. In 2002, the World Health Organization launched an initiative to improve children’s environmental protection effort. Here, we review major environmental pollutants and related hazards among children and adolescents.

Children face the excitement of a changing world but also encounter environmental threats to their health that were neither known nor suspected several decades ago. Children are at particular risk of exposure to pollutants that are widely dispersed in the air, water, and food. Children and adolescents are exposed to chemical, physical, and biological risks at home, in school, and elsewhere. Actions are needed to reduce these risks for children exposed to a series of environmental hazards. Exposure to a number of persistent environmental pollutants including air pollutants, endocrine disruptors, noise, electromagnetic waves (EMWs), tobacco and other noxious substances, heavy metals, and microplastics, is linked to damage to the nervous and immune systems and affects reproductive function and development. Exposure to environmental hazards is responsible for several acute and chronic diseases that have replaced infectious diseases as the principal cause of illnesses and death during childhood. Children are disproportionately exposed to environmental toxicities. Children drink more water, eat more food, and breathe more frequently than adults. As a result, children have a substantially heavier exposure to toxins present in water, food, or air than adults. In addition, their hand-to-mouth behaviors and the fact that they live and play close to the ground make them more vulnerable than adults. Children undergo rapid growth and development processes that are easily disrupted. These systems are very delicate and cannot adequately repair thetional development in children’s environmental health was the Declaration of the Environment Leaders of the Eight on Children’s Environmental Health by the Group of Eight. In 2002, the World Health Organization launched an initiative to improve children’s environmental protection effort. Here, we review major environmental pollutants and related hazards among children and adolescents.

In recent years, next-generation sequencing (NGS)–based genetic testing has become crucial in cancer care. While its primary objective is to identify actionable genetic alterations to guide treatment decisions, its scope has broadened to encompass aiding in pathological diagnosis and exploring resistance mechanisms. With the ongoing expansion in NGS application and reliance, a compelling necessity arises for expert consensus on its application in solid cancers. To address this demand, the forthcoming recommendations not only provide pragmatic guidance for the clinical use of NGS but also systematically classify actionable genes based on specific cancer types. Additionally, these recommendations will incorporate expert perspectives on crucial biomarkers, ensuring informed decisions regarding circulating tumor DNA panel testing.

Purpose: Notable effectiveness of trastuzumab deruxtecan in patients with human epidermal growth factor receptor 2 (HER2)–low advanced breast cancer (BC) has focused pathologists’ attention. We studied the incidence and clinicopathologic characteristics of HER2-low BC, and the effects of immunohistochemistry (IHC) associated factors on HER2 IHC results. Materials and Methods: The Breast Pathology Study Group of the Korean Society of Pathologists conducted a nationwide study using real-world data on HER2 status generated between January 2022 and December 2022. Information on HER2 IHC protocols at each participating institution was also collected. Results: Total 11,416 patients from 25 institutions included in this study. Of these patients, 40.7% (range, 6.0% to 76.3%) were classified as HER2-zero, 41.7% (range, 10.5% to 69.1%) as HER2-low, and 17.5% (range, 6.7% to 34.0%) as HER2-positive. HER2-low tumors were associated with positive estrogen receptor and progesterone receptor statuses (p < 0.001 and p < 0.001, respectively). Antigen retrieval times (≥ 36 minutes vs. < 36 minutes) and antibody incubation times (≥ 12 minutes vs. < 12 minutes) affected on the frequency of HER2 IHC 1+ BC at institutions using the PATHWAY HER2 (4B5) IHC assay and BenchMark XT or Ultra staining instruments. Furthermore, discordant results between core needle biopsy and subsequent resection specimen HER2 statuses were observed in 24.1% (787/3,259) of the patients. Conclusion The overall incidence of HER2-low BC in South Korea concurs with those reported in previously published studies. Significant inter-institutional differences in HER2 IHC protocols were observed, and it may have impact on HER2-low status. Thus, we recommend standardizing HER2 IHC conditions to ensure precise patient selection for targeted therapy.

Background/Aims: Tegoprazan is a novel potassium-competitive acid blocker that has beneficial effects on acid-related disorders such as gastroesophageal reflux and peptic ulcer diseases.This study aimed to validate the effect of tegoprazan on endoscopic submucosal dissection (ESD)-induced artificial ulcers. Methods: Patients from 16 centers in Korea who underwent ESD for gastric neoplasia were enrolled. After ESD, pantoprazole was administered intravenously for 48 hours. The patients were randomly allocated to either the tegoprazan or esomeprazole group. Tegoprazan 50 mg or esomeprazole 40 mg were administered for 4 weeks, after which gastroscopic evaluation was performed. If the artificial ulcer had not healed, the same dose of tegoprazan or esomeprazole was administered for an additional 4 weeks, and a gastroscopic evaluation was performed. Results: One hundred sixty patients were enrolled in this study. The healing rates of artificial ulcers at 4 weeks were 30.3% (23/76) and 22.1% (15/68) in the tegoprazan and esomeprazole groups, respectively (p=0.006). At 8 weeks after ESD, the cumulative ulcer healing rates were 73.7% (56/76) and 77.9% (53/68) in the tegoprazan and esomeprazole groups, respectively (p=0.210). Delayed bleeding occurred in two patients in the tegoprazan group (2.6%) and in one patient in the esomeprazole group (1.5%). Other adverse events were negligible in both groups. Conclusions Tegoprazan showed similar effects on post-ESD artificial ulcer healing in comparison with esomeprazole.

In recent years, next-generation sequencing (NGS)–based genetic testing has become crucial in cancer care. While its primary objective is to identify actionable genetic alterations to guide treatment decisions, its scope has broadened to encompass aiding in pathological diagnosis and exploring resistance mechanisms. With the ongoing expansion in NGS application and reliance, a compelling necessity arises for expert consensus on its application in solid cancers. To address this demand, the forthcoming recommendations not only provide pragmatic guidance for the clinical use of NGS but also systematically classify actionable genes based on specific cancer types. Additionally, these recommendations will incorporate expert perspectives on crucial biomarkers, ensuring informed decisions regarding circulating tumor DNA panel testing.

Objective: : The use of indocyanine green videoangiography (ICG-VA) to assess blood flow in the brain during cerebrovascular surgery has been increasing. Clinical studies on ICG-VA have predominantly focused on qualitative analysis. However, quantitative analysis numerical modelling for time profiling enables a more accurate evaluation of blood flow kinetics. In this study, we established a multiple exponential modified Gaussian (multi-EMG) model for quantitative ICG-VA to understand accurately the status of cerebral hemodynamics. Methods: : We obtained clinical data of cerebral blood flow acquired the quantitative analysis ICG-VA during cerebrovascular surgery. Varied asymmetric peak functions were compared to find the most matching function form with clinical data by using a nonlinear regression algorithm. To verify the result of the nonlinear regression, the mode function was applied to various types of data. Results: : The proposed multi-EMG model is well fitted to the clinical data. Because the primary parameters—growth and decay rates, and peak centres and heights—of the model are characteristics of model function, they provide accurate reference values for assessing cerebral hemodynamics in various conditions. In addition, the primary parameters can be estimated on the curves with partially missed data. The accuracy of the model estimation was verified by a repeated curve fitting method using manipulation of missing data. Conclusion : The multi-EMG model can possibly serve as a universal model for cerebral hemodynamics in a comparison with other asymmetric peak functions. According to the results, the model can be helpful for clinical research assessment of cerebrovascular hemodynamics in a clinical setting.