Purpose: Appropriate preclinical mouse models are needed to evaluate the response to immunotherapeutic agents. Immunocompetent mouse models have rarely been reported for gastric cancer. Thus, we investigated immunophenotypes and responses to immune checkpoint inhibitor (ICI) in immunocompetent mouse models using various murine gastric cancer cell lines. Materials and Methods: We constructed subcutaneous syngeneic tumors with murine gastric cancer cell lines, YTN3 and YTN16, in C57BL/6J mice. Mice were intraperitoneally treated with IgG isotype control or an anti–programmed death-ligand 1 (PD-L1) neutralizing antibody. We used immunohistochemistry to evaluate the tumor-infiltrating immune cells of formalin-fixed paraffin-embedded mouse tumor tissues. We compared the protein and RNA expression between YTN3 and YTN16 cell lines using a mouse cytokine array and RNA sequencing. Results: The mouse tumors revealed distinct histological and molecular characteristics. YTN16 cells showed upregulation of genes and proteins related to immunosuppression, such as Ccl2 (CCL2) and Csf1 (M-CSF). Macrophages and exhausted T cells were more enriched in YTN16 tumors than in YTN3 tumors. Several YTN3 tumors were completely regressed by the PD-L1 inhibitor, whereas YTN16 tumors were unaffected. Although treatment with a PD-L1 inhibitor increased infiltration of T cells in both the tumors, the proportion of exhausted immune cells did not decrease in the non-responder group. Conclusion We confirmed the histological and molecular features of cancer cells with various responses to ICI. Our models can be used in preclinical research on ICI resistance mechanisms to enhance clinical efficacy.

Background: This study aimed to examine the association between coffee or green tea consumption and ferritin or hemoglobin levels in premenopausal women. Methods: We used the fifth Korea National Health and Nutrition Examination Survey (2010–2012), and a total of 4,322 individuals were surveyed. In women of reproductive age, average ferritin and hemoglobin levels were calculated according to coffee or green tea consumption. Covariates included in the analysis were demographic variables, such as age, body mass index, education, drinking, smoking, history of hypertension, history of diabetes diagnosis, physical activity, total energy intake, and daily iron intake. Results: In 4,322 participants, the average hemoglobin level was 12.90±0.02 g/dL, and the average level of ferritin was 31.95±0.67 ng/mL. As a result of testing, correlation between ferritin and coffee intake and difference in ferritin levels according to coffee consumption was significant (P<0.05). In this study, a post hoc test indicated that ferritin level significantly differed between one and two cups, two and three cups, and three and one cup groups (overall P<0.001). Additionally, there was a negative correlation between ferritin level and coffee intake; ferritin level decreased by 2.09 ng/mL with a one-cup increase in daily coffee consumption. Conclusion In premenopausal women, coffee intake is associated with low serum ferritin levels. Our results indicate that drinking >2 cups of coffee significantly affect ferritin levels in Korean premenopausal women.

Background: Since the World Health Organization’s pandemic declaration in March 2020, Korea has witnessed shifts in lifestyle behaviors, impacting habits tied to socioeconomic status and contributing to metabolic syndrome (MetS). To investigate this issue, the current study aimed to investigate changes in MetS prevalence, particularly based on income levels before and after the coronavirus disease 2019 (COVID-19) pandemic. Methods: This study used data from the 8th Korea National Health and Nutrition Examination Survey (2019–2020). A total of 6,840 individuals aged 30–65 years were included in this study. Household income was divided into high (≥75th percentile), middle (25–75th percentile), and low (≤25th percentile). A multivariable logistic regression analysis was performed to explore the interaction between this association before and after the COVID-19 pandemic. Results: A statistically significant difference was found in the prevalence of MetS before and after the COVID-19 pandemic (26.7% to 30.2%, P=0.001). These changes differed based on income levels. The increase in the prevalence of MetS was statistically significant in the low- and high-income groups but not in the middle-income group (low: 8.0%p increase [P=0.039], middle: 1.0%p increase [P=0.522], high: 6.4%p increase [P<0.001]). The interaction between household income and the COVID-19 pandemic on MetS was statistically significant (P for interaction=0.032). Conclusion This study revealed that P for interaction between household income, MetS, and the period before and after the COVID-19 pandemic was significant. Changes in physical activity and eating habits during the COVID-19 pandemic may have contributed to these differences.

Background: Adolescent dependency on smartphones is the highest among all age groups. Adolescents can be influenced to evaluate their body image by popular ideals about beautiful bodies via smartphone content, which can cause body image distortion. This study aimed to examine the association between body image distortion and smartphone dependency and the duration of smartphone usage among Korean adolescents. Methods: This study used data from the 16th Korean Youth Risk Behavior Web-Based Survey (2020), and included 42,981 participants, who were grouped according to self-reported duration of smartphone usage and smartphone dependency, as measured by a questionnaire. Body image distortion is defined as an exaggerated subjective body image compared to the actual body image. Multivariable-adjusted logistic regression was used to determine the odds ratios (ORs) with 95% confidence intervals (CIs) of body image distortion on smartphone dependency and usage time after adjusting for various factors related to body image distortion. Results: Among the 42,981 participants, both moderate and high levels of smartphone dependency were associated with body image distortion in boys (moderate: adjusted OR [aOR], 1.11; 95% CI, 1.01–1.22; high: aOR, 1.18; 95% CI, 1.05–1.32) and girls (moderate: aOR, 1.14; 95% CI, 1.05–1.23; high: aOR, 1.30; 95% CI, 1.18–1.42) compared to the low-level dependency group. However, no significant association was found between smartphone usage duration and body image distortion. Conclusion Our study demonstrated that moderate to high levels of smartphone dependency are associated with body image distortion in adolescents. Therefore, it is necessary to establish strategies for checking and managing adolescents’ smartphone dependence.

Background: Since the World Health Organization’s pandemic declaration in March 2020, Korea has witnessed shifts in lifestyle behaviors, impacting habits tied to socioeconomic status and contributing to metabolic syndrome (MetS). To investigate this issue, the current study aimed to investigate changes in MetS prevalence, particularly based on income levels before and after the coronavirus disease 2019 (COVID-19) pandemic. Methods: This study used data from the 8th Korea National Health and Nutrition Examination Survey (2019–2020). A total of 6,840 individuals aged 30–65 years were included in this study. Household income was divided into high (≥75th percentile), middle (25–75th percentile), and low (≤25th percentile). A multivariable logistic regression analysis was performed to explore the interaction between this association before and after the COVID-19 pandemic. Results: A statistically significant difference was found in the prevalence of MetS before and after the COVID-19 pandemic (26.7% to 30.2%, P=0.001). These changes differed based on income levels. The increase in the prevalence of MetS was statistically significant in the low- and high-income groups but not in the middle-income group (low: 8.0%p increase [P=0.039], middle: 1.0%p increase [P=0.522], high: 6.4%p increase [P<0.001]). The interaction between household income and the COVID-19 pandemic on MetS was statistically significant (P for interaction=0.032). Conclusion This study revealed that P for interaction between household income, MetS, and the period before and after the COVID-19 pandemic was significant. Changes in physical activity and eating habits during the COVID-19 pandemic may have contributed to these differences.

Background: Adolescent dependency on smartphones is the highest among all age groups. Adolescents can be influenced to evaluate their body image by popular ideals about beautiful bodies via smartphone content, which can cause body image distortion. This study aimed to examine the association between body image distortion and smartphone dependency and the duration of smartphone usage among Korean adolescents. Methods: This study used data from the 16th Korean Youth Risk Behavior Web-Based Survey (2020), and included 42,981 participants, who were grouped according to self-reported duration of smartphone usage and smartphone dependency, as measured by a questionnaire. Body image distortion is defined as an exaggerated subjective body image compared to the actual body image. Multivariable-adjusted logistic regression was used to determine the odds ratios (ORs) with 95% confidence intervals (CIs) of body image distortion on smartphone dependency and usage time after adjusting for various factors related to body image distortion. Results: Among the 42,981 participants, both moderate and high levels of smartphone dependency were associated with body image distortion in boys (moderate: adjusted OR [aOR], 1.11; 95% CI, 1.01–1.22; high: aOR, 1.18; 95% CI, 1.05–1.32) and girls (moderate: aOR, 1.14; 95% CI, 1.05–1.23; high: aOR, 1.30; 95% CI, 1.18–1.42) compared to the low-level dependency group. However, no significant association was found between smartphone usage duration and body image distortion. Conclusion Our study demonstrated that moderate to high levels of smartphone dependency are associated with body image distortion in adolescents. Therefore, it is necessary to establish strategies for checking and managing adolescents’ smartphone dependence.

Background: Since the World Health Organization’s pandemic declaration in March 2020, Korea has witnessed shifts in lifestyle behaviors, impacting habits tied to socioeconomic status and contributing to metabolic syndrome (MetS). To investigate this issue, the current study aimed to investigate changes in MetS prevalence, particularly based on income levels before and after the coronavirus disease 2019 (COVID-19) pandemic. Methods: This study used data from the 8th Korea National Health and Nutrition Examination Survey (2019–2020). A total of 6,840 individuals aged 30–65 years were included in this study. Household income was divided into high (≥75th percentile), middle (25–75th percentile), and low (≤25th percentile). A multivariable logistic regression analysis was performed to explore the interaction between this association before and after the COVID-19 pandemic. Results: A statistically significant difference was found in the prevalence of MetS before and after the COVID-19 pandemic (26.7% to 30.2%, P=0.001). These changes differed based on income levels. The increase in the prevalence of MetS was statistically significant in the low- and high-income groups but not in the middle-income group (low: 8.0%p increase [P=0.039], middle: 1.0%p increase [P=0.522], high: 6.4%p increase [P<0.001]). The interaction between household income and the COVID-19 pandemic on MetS was statistically significant (P for interaction=0.032). Conclusion This study revealed that P for interaction between household income, MetS, and the period before and after the COVID-19 pandemic was significant. Changes in physical activity and eating habits during the COVID-19 pandemic may have contributed to these differences.

Background: Adolescent dependency on smartphones is the highest among all age groups. Adolescents can be influenced to evaluate their body image by popular ideals about beautiful bodies via smartphone content, which can cause body image distortion. This study aimed to examine the association between body image distortion and smartphone dependency and the duration of smartphone usage among Korean adolescents. Methods: This study used data from the 16th Korean Youth Risk Behavior Web-Based Survey (2020), and included 42,981 participants, who were grouped according to self-reported duration of smartphone usage and smartphone dependency, as measured by a questionnaire. Body image distortion is defined as an exaggerated subjective body image compared to the actual body image. Multivariable-adjusted logistic regression was used to determine the odds ratios (ORs) with 95% confidence intervals (CIs) of body image distortion on smartphone dependency and usage time after adjusting for various factors related to body image distortion. Results: Among the 42,981 participants, both moderate and high levels of smartphone dependency were associated with body image distortion in boys (moderate: adjusted OR [aOR], 1.11; 95% CI, 1.01–1.22; high: aOR, 1.18; 95% CI, 1.05–1.32) and girls (moderate: aOR, 1.14; 95% CI, 1.05–1.23; high: aOR, 1.30; 95% CI, 1.18–1.42) compared to the low-level dependency group. However, no significant association was found between smartphone usage duration and body image distortion. Conclusion Our study demonstrated that moderate to high levels of smartphone dependency are associated with body image distortion in adolescents. Therefore, it is necessary to establish strategies for checking and managing adolescents’ smartphone dependence.

Background: Since the World Health Organization’s pandemic declaration in March 2020, Korea has witnessed shifts in lifestyle behaviors, impacting habits tied to socioeconomic status and contributing to metabolic syndrome (MetS). To investigate this issue, the current study aimed to investigate changes in MetS prevalence, particularly based on income levels before and after the coronavirus disease 2019 (COVID-19) pandemic. Methods: This study used data from the 8th Korea National Health and Nutrition Examination Survey (2019–2020). A total of 6,840 individuals aged 30–65 years were included in this study. Household income was divided into high (≥75th percentile), middle (25–75th percentile), and low (≤25th percentile). A multivariable logistic regression analysis was performed to explore the interaction between this association before and after the COVID-19 pandemic. Results: A statistically significant difference was found in the prevalence of MetS before and after the COVID-19 pandemic (26.7% to 30.2%, P=0.001). These changes differed based on income levels. The increase in the prevalence of MetS was statistically significant in the low- and high-income groups but not in the middle-income group (low: 8.0%p increase [P=0.039], middle: 1.0%p increase [P=0.522], high: 6.4%p increase [P<0.001]). The interaction between household income and the COVID-19 pandemic on MetS was statistically significant (P for interaction=0.032). Conclusion This study revealed that P for interaction between household income, MetS, and the period before and after the COVID-19 pandemic was significant. Changes in physical activity and eating habits during the COVID-19 pandemic may have contributed to these differences.

Background: Adolescent dependency on smartphones is the highest among all age groups. Adolescents can be influenced to evaluate their body image by popular ideals about beautiful bodies via smartphone content, which can cause body image distortion. This study aimed to examine the association between body image distortion and smartphone dependency and the duration of smartphone usage among Korean adolescents. Methods: This study used data from the 16th Korean Youth Risk Behavior Web-Based Survey (2020), and included 42,981 participants, who were grouped according to self-reported duration of smartphone usage and smartphone dependency, as measured by a questionnaire. Body image distortion is defined as an exaggerated subjective body image compared to the actual body image. Multivariable-adjusted logistic regression was used to determine the odds ratios (ORs) with 95% confidence intervals (CIs) of body image distortion on smartphone dependency and usage time after adjusting for various factors related to body image distortion. Results: Among the 42,981 participants, both moderate and high levels of smartphone dependency were associated with body image distortion in boys (moderate: adjusted OR [aOR], 1.11; 95% CI, 1.01–1.22; high: aOR, 1.18; 95% CI, 1.05–1.32) and girls (moderate: aOR, 1.14; 95% CI, 1.05–1.23; high: aOR, 1.30; 95% CI, 1.18–1.42) compared to the low-level dependency group. However, no significant association was found between smartphone usage duration and body image distortion. Conclusion Our study demonstrated that moderate to high levels of smartphone dependency are associated with body image distortion in adolescents. Therefore, it is necessary to establish strategies for checking and managing adolescents’ smartphone dependence.