Purpose: Human epidermal growth factor receptor 2 (HER2) is amplified or overexpressed in various malignancies, including breast and gastric cancers, and is associated with poor prognosis. Although HER2-targeted therapies, such as trastuzumab, improve outcomes in HER2-positive tumors, resistance often develops, and HER2-low tumors remain largely untargeted. Trastuzumab deruxtecan (T-DXd; DS-8201a) is a HER2-targeted antibody-drug conjugate with potent activity in HER2-positive and HER2-low tumors. This study evaluates its antitumor mechanisms and efficacy in HER2-positive, HER2-low, and homologous recombination deficiency (HRD)–associated models. Materials and Methods: Effects of T-DXd were assessed in cancer cell lines with diverse HER2 expression and HRD status. In vivo efficacy was evaluated using a xenograft model derived from HER2-low SNU-601 gastric cancer cells. Results: T-DXd reduced HER2 phosphorylation and downstream signaling (AKT, ERK) in HER2-positive cells. It induced DNA damage accumulation, as evidenced by increased γH2AX and p-Chk1 expression, and triggered apoptosis through cleaved poly(ADP-ribose) polymerase and caspase-3 activation, confirmed by annexin V staining. Similar effects were observed in HER2-low cells, with greater sensitivity in HRD cells. In xenografts, T-DXd reduced tumor volume by up to 80% at 4 mg/kg and 10 mg/kg. Histological analyses showed decreased Ki-67 and increased apoptosis. Furthermore, T-DXd induced G2/M cell cycle arrest and nuclear anaplasia, suggesting disruption of chromosomal stability as a potential antitumor mechanism. No significant toxicity, including body weight loss, was observed. Conclusion These findings highlight T-DXd’s effectiveness in HER2-low and HRD tumors, supporting its broader clinical application, including strategies targeting DNA damage repair pathways.

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.

Purpose: This pilot study aimed to evaluate the effects of the Floating Nurse system designed to improve nurses’ shift work conditions on individual and organizational outcomes. Methods: A non-equivalent posttest-only control group design was used. Individual-level data on job satisfaction, work-life balance, and turnover intention were collected through anonymous self-administered questionnaires from January 16 to 27, 2023, six months after system implementation. Organizational-level turnover rates were obtained from administrative records for the period before and after implementation (January-June and July-December 2022). The study included 352 nurses from 38 general wards at a tertiary hospital in Seoul-250 from 27 wards where the system was implemented (participation group) and 102 from 11 wards without the system (non-participation group).Multilevel modeling was applied, accounting for individual-level (Level 1) and ward-level (Level 2) factors. Results: Job satisfaction was significantly higher in the participation group than in the non-participation group (B=2.28, p=.008). Work-life balance was higher but not statistically significant (B=4.10, p=.120), and turnover intention showed no significant difference (B=-0.48, p=.204). Turnover rates decreased in both groups, with a larger reduction in the participation group (from 2.5% to 1.8%) than in the non-participation group (from 4.5% to 3.5%). Conclusion The Floating Nurse System improved job satisfaction and contributed to lower turnover rates, suggesting potential benefits for workforce stability. Although improvements in work-life balance and turnover intention were not statistically significant, enhanced job satisfaction may indirectly mitigate turnover intention. Further multi-site and longitudinal studies are warranted to confirm long-term effects.

Objectives: Eveningness predominates in adolescence. Morningness has been reported to be associated with mental toughness via resilience. Morningness could be related to healthy sleep habits and a good personality. Methods: Sleep-related behaviors, such as weekend oversleep, social jetlag, and daytime sunlight exposure between 10:00 and 15:00, were evaluated using sleep-related questionnaires. Morningness-eveningness questionnaire, insomnia severity index, Epworth sleepiness scale, hospital anxiety and depression scale and defense style questionnaire were used. This study includes 1,610 high school students. Results: Multiple linear regression analysis revealed that morningness is predicted by male sex (β=0.115, t=4.769, p<0.001) and greater adaptive (β=0.092, t=3.506, p<0.001) and self-suppressive defense styles (β=0.072, t=2.192, p=0.029) and lesser immature defense styles (β=-0.163, t=-4.782, p<0.001) after controlling for age, sleep quality, depression, anxiety. Morningness is also predicted by greater sublimation (β=0.09, t=3.541, p<0.001) and reaction formation (β=0.112, t=4.488, p<0.001) and lesser consumption (β=-0.062, t=-2.501, p=0.012), passive aggression (β=-0.101, t=-3.747, p<0.001) and withdrawal (β=-0.084, t=-2.955, p=0.003), and male sex (β=0.117, t=4.896, p<0.001) after controlling for age, sleep quality, depression, and anxiety. Conclusion Morniness in adolescence may be related to a positive personality. Promoting morningness might be related to healthy development in personality.

Objectives: Eveningness predominates in adolescence. Morningness has been reported to be associated with mental toughness via resilience. Morningness could be related to healthy sleep habits and a good personality. Methods: Sleep-related behaviors, such as weekend oversleep, social jetlag, and daytime sunlight exposure between 10:00 and 15:00, were evaluated using sleep-related questionnaires. Morningness-eveningness questionnaire, insomnia severity index, Epworth sleepiness scale, hospital anxiety and depression scale and defense style questionnaire were used. This study includes 1,610 high school students. Results: Multiple linear regression analysis revealed that morningness is predicted by male sex (β=0.115, t=4.769, p<0.001) and greater adaptive (β=0.092, t=3.506, p<0.001) and self-suppressive defense styles (β=0.072, t=2.192, p=0.029) and lesser immature defense styles (β=-0.163, t=-4.782, p<0.001) after controlling for age, sleep quality, depression, anxiety. Morningness is also predicted by greater sublimation (β=0.09, t=3.541, p<0.001) and reaction formation (β=0.112, t=4.488, p<0.001) and lesser consumption (β=-0.062, t=-2.501, p=0.012), passive aggression (β=-0.101, t=-3.747, p<0.001) and withdrawal (β=-0.084, t=-2.955, p=0.003), and male sex (β=0.117, t=4.896, p<0.001) after controlling for age, sleep quality, depression, and anxiety. Conclusion Morniness in adolescence may be related to a positive personality. Promoting morningness might be related to healthy development in personality.

Objectives: Eveningness predominates in adolescence. Morningness has been reported to be associated with mental toughness via resilience. Morningness could be related to healthy sleep habits and a good personality. Methods: Sleep-related behaviors, such as weekend oversleep, social jetlag, and daytime sunlight exposure between 10:00 and 15:00, were evaluated using sleep-related questionnaires. Morningness-eveningness questionnaire, insomnia severity index, Epworth sleepiness scale, hospital anxiety and depression scale and defense style questionnaire were used. This study includes 1,610 high school students. Results: Multiple linear regression analysis revealed that morningness is predicted by male sex (β=0.115, t=4.769, p<0.001) and greater adaptive (β=0.092, t=3.506, p<0.001) and self-suppressive defense styles (β=0.072, t=2.192, p=0.029) and lesser immature defense styles (β=-0.163, t=-4.782, p<0.001) after controlling for age, sleep quality, depression, anxiety. Morningness is also predicted by greater sublimation (β=0.09, t=3.541, p<0.001) and reaction formation (β=0.112, t=4.488, p<0.001) and lesser consumption (β=-0.062, t=-2.501, p=0.012), passive aggression (β=-0.101, t=-3.747, p<0.001) and withdrawal (β=-0.084, t=-2.955, p=0.003), and male sex (β=0.117, t=4.896, p<0.001) after controlling for age, sleep quality, depression, and anxiety. Conclusion Morniness in adolescence may be related to a positive personality. Promoting morningness might be related to healthy development in personality.

Objectives: Eveningness predominates in adolescence. Morningness has been reported to be associated with mental toughness via resilience. Morningness could be related to healthy sleep habits and a good personality. Methods: Sleep-related behaviors, such as weekend oversleep, social jetlag, and daytime sunlight exposure between 10:00 and 15:00, were evaluated using sleep-related questionnaires. Morningness-eveningness questionnaire, insomnia severity index, Epworth sleepiness scale, hospital anxiety and depression scale and defense style questionnaire were used. This study includes 1,610 high school students. Results: Multiple linear regression analysis revealed that morningness is predicted by male sex (β=0.115, t=4.769, p<0.001) and greater adaptive (β=0.092, t=3.506, p<0.001) and self-suppressive defense styles (β=0.072, t=2.192, p=0.029) and lesser immature defense styles (β=-0.163, t=-4.782, p<0.001) after controlling for age, sleep quality, depression, anxiety. Morningness is also predicted by greater sublimation (β=0.09, t=3.541, p<0.001) and reaction formation (β=0.112, t=4.488, p<0.001) and lesser consumption (β=-0.062, t=-2.501, p=0.012), passive aggression (β=-0.101, t=-3.747, p<0.001) and withdrawal (β=-0.084, t=-2.955, p=0.003), and male sex (β=0.117, t=4.896, p<0.001) after controlling for age, sleep quality, depression, and anxiety. Conclusion Morniness in adolescence may be related to a positive personality. Promoting morningness might be related to healthy development in personality.

Objectives: Eveningness predominates in adolescence. Morningness has been reported to be associated with mental toughness via resilience. Morningness could be related to healthy sleep habits and a good personality. Methods: Sleep-related behaviors, such as weekend oversleep, social jetlag, and daytime sunlight exposure between 10:00 and 15:00, were evaluated using sleep-related questionnaires. Morningness-eveningness questionnaire, insomnia severity index, Epworth sleepiness scale, hospital anxiety and depression scale and defense style questionnaire were used. This study includes 1,610 high school students. Results: Multiple linear regression analysis revealed that morningness is predicted by male sex (β=0.115, t=4.769, p<0.001) and greater adaptive (β=0.092, t=3.506, p<0.001) and self-suppressive defense styles (β=0.072, t=2.192, p=0.029) and lesser immature defense styles (β=-0.163, t=-4.782, p<0.001) after controlling for age, sleep quality, depression, anxiety. Morningness is also predicted by greater sublimation (β=0.09, t=3.541, p<0.001) and reaction formation (β=0.112, t=4.488, p<0.001) and lesser consumption (β=-0.062, t=-2.501, p=0.012), passive aggression (β=-0.101, t=-3.747, p<0.001) and withdrawal (β=-0.084, t=-2.955, p=0.003), and male sex (β=0.117, t=4.896, p<0.001) after controlling for age, sleep quality, depression, and anxiety. Conclusion Morniness in adolescence may be related to a positive personality. Promoting morningness might be related to healthy development in personality.

Objectives: Excess deaths, an indicator that compares total mortality rates before and during a pandemic, offer a comprehensive view of the pandemic’s impact. However, discrepancies may arise from variations in estimating expected deaths. This study aims to compare excess deaths in Korea during the coronavirus disease 2019 pandemic using 3 methods and to analyze patterns using the most appropriate method. Methods: Expected deaths from 2020 to 2022 were estimated using mortality data from 2015-2019 as reference years. This estimation employed 3 approaches: (1) simple average, (2) age-adjusted average, and (3) age-adjusted linear regression. Excess deaths by age, gender, and cause of death were also presented. Results: The number of excess deaths varied depending on the estimation method used, reaching its highest point with the simple average and its lowest with the age-adjusted average. Age-adjusted linear regression, which accounts for both the aging population and declining mortality rates, was considered most appropriate. Using this model, excess deaths were estimated at 0.3% for 2020, 4.0% for 2021, and 20.7% for 2022. Excess deaths surged among individuals in their 20s throughout the pandemic, largely attributed to a rise in self-harm and suicide. Additionally, the results indicated sharp increases in deaths associated with “endocrine, nutritional, and metabolic diseases” and “symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified.” Conclusions Substantial variations in excess deaths were evident based on estimation method, with a notable increase in 2022. The heightened excess deaths among young adults and specific causes underscore key considerations for future pandemic responses.

Purpose: The current study provides national cancer statistics and their secular trends in Korea, including incidence, mortality, survival, and prevalence in 2020. Materials and Methods: Incidence, survival, and prevalence rates of cancer were calculated using the Korea National Cancer Incidence Database, from 1999 to 2020, with survival follow-up until December 31, 2021. Deaths from cancer were assessed using causes-of-death data obtained from Statistics Korea. Results: The number of new cancer diagnoses in 2020 decreased by 9,218 cases (3.6%) compared to 2019. In 2020, newly diagnosed cancer cases and deaths from cancer were reported as 247,952 (age-standardized rate [ASR], 262.2 per 100,000) and 82,204 (ASR, 69.9 per 100,000), respectively. The overall cancer incidence rates increased by 3.3% annually from 1999 to 2012, and decreased by 5.0% annually from 2012 to 2015, thereafter, followed by nonsignificant changes. Cancer mortality rates have been decreasing since 2002, with more rapid decline in recent years. The 5-year relative survival between 2016 and 2020 was 71.5%, which contributed to prevalent cases reaching over 2.2 million in 2020. Conclusion In 2020, the number of newly diagnosed cancer patients decreased due to the coronavirus disease 2019 pandemic, but the overall trend is on the rise. Cancer survival rates have improved over the past decades. As the number of cancer survivors increases, a comprehensive cancer control strategy should be implemented in line with the changing aspects of cancer statistics. The long-term impact of the coronavirus disease 2019 pandemic on cancer statistics needs to be investigated in the future.