Background SARS-CoV-2 (severe acute respiratory coronavirus 2) was spreading rapidly in South Korea at the end of February 2020 following its initial outbreak in China, making Korea the new center of global attention. The role of social media amid the current coronavirus disease (COVID-19) pandemic has often been criticized, but little systematic research has been conducted on this issue. Social media functions as a convenient source of information in pandemic situations. Objective Few infodemiology studies have applied network analysis in conjunction with content analysis. This study investigates information transmission networks and news-sharing behaviors regarding COVID-19 on Twitter in Korea. The real time aggregation of social media data can serve as a starting point for designing strategic messages for health campaigns and establishing an effective communication system during this outbreak. Methods Korean COVID-19-related Twitter data were collected on February 29, 2020. Our final sample comprised of 43,832 users and 78,233 relationships on Twitter. We generated four networks in terms of key issues regarding COVID-19 in Korea. This study comparatively investigates how COVID-19-related issues have circulated on Twitter through network analysis. Next, we classified top news channels shared via tweets. Lastly, we conducted a content analysis of news frames used in the top-shared sources. Results The network analysis suggests that the spread of information was faster in the Coronavirus network than in the other networks (Corona19, Shincheon, and Daegu). People who used the word “Coronavirus” communicated more frequently with each other. The spread of information was faster, and the diameter value was lower than for those who used other terms. Many of the news items highlighted the positive roles being played by individuals and groups, directing readers’ attention to the crisis. Ethical issues such as deviant behavior among the population and an entertainment frame highlighting celebrity donations also emerged often. There was a significant difference in the use of nonportal (n=14) and portal news (n=26) sites between the four network types. The news frames used in the top sources were similar across the networks (P=.89, 95% CI 0.004-0.006). Tweets containing medically framed news articles (mean 7.571, SD 1.988) were found to be more popular than tweets that included news articles adopting nonmedical frames (mean 5.060, SD 2.904; N=40, P=.03, 95% CI 0.169-4.852). Conclusions Most of the popular news on Twitter had nonmedical frames. Nevertheless, the spillover effect of the news articles that delivered medical information about COVID-19 was greater than that of news with nonmedical frames. Social media network analytics cannot replace the work of public health officials; however, monitoring public conversations and media news that propagates rapidly can assist public health professionals in their complex and fast-paced decision-making processes.

BackgroundThe aim of this study is to profile the cytokines and immune cells of body fluid from metastatic gastric cancer (mGC), and evaluate the potential role as a prognostic factor and the feasibility as a predictive biomarker or monitoring source for immune checkpoint inhibitor.MethodsBody fluid including ascites and pleural fluid were obtained from 55 mGC patients and 24 matched blood. VEGF-A, IL-10, and TGF-β1 were measured and immune cells were profiled by fluorescence assisted cell sorting (FACS).ResultsVEGF-A and IL-10 were significantly higher in body fluid than in plasma of mGC. Proportion of T lymphocytes with CD69 or PD-1, memory T cell marked with CD45RO, and number of Foxp3+ T regulatory cells (Tregs) were significantly higher in body fluid than those in blood of mGC. Proportion of CD8 T lymphocyte with memory marker (CD45RO) and activation marker (HLA-DR), CD3 T lymphocyte with PD-1, and number of FoxP3+ Tregs were identified as independent prognostic factors. When patients were classified by molecular subgroups of primary tumor, VEGF-A was significantly higher in genomically stable (GS)-like group than that in chromosomal instability (CIN)-like group while PD-L1 positive tumor cells (%) showed opposite results. Monitoring immune dynamics using body fluid was also feasible. Early activated T cell marked with CD25 was significantly increased in chemotherapy treated group.ConclusionsBy analyzing cytokines and proportion of immune cells in body fluid, prognosis of patients with mGC can be predicted. Immune monitoring using body fluid may provide more effective treatment for patients with mGC.Electronic supplementary materialThe online version of this article (10.1186/s40425-019-0708-8) contains supplementary material, which is available to authorized users.

Background Mesothelin is overexpressed in many solid tumors, and recent studies have shown that mesothelin expression is associated with poor outcomes in several malignant tumors and may play a role in cancer progression. Clinical trials of mesothelin‐targeted immunotherapies are currently under way, but the correlation between mesothelin expression and gastric cancer prognosis is still unclear. Subjects, Materials, and Methods Mesothelin expression in tumor cells was evaluated immunohistochemically in 958 patients with advanced gastric cancer and interpreted according to the intensity and extent of staining. Samples were scored from 0 to 2, with high expression defined as a score of 2. Clinicopathological factors, overall survival (OS), recurrence‐free survival (RFS), and sites of initial recurrence, including peritoneal recurrence, were evaluated. Staging was performed according to the American Joint Committee on Cancer 7th edition. Results High mesothelin expression was observed in 49.7% of patients and significantly associated with high pathologic T (p = .021) and peritoneal recurrence (p = .018). Multivariate survival analysis showed that high mesothelin expression was independently associated with poor RFS (p = .001), OS (p = .001), and peritoneal recurrence (p = .002) in addition to stage, lymphovascular invasion, and Lauren classification. In a subgroup analysis of peritoneal recurrence, high mesothelin expression was also an independent prognostic factor in stage III (p = .013) and diffuse/mixed type gastric cancer (p = .010). Conclusion High mesothelin expression is correlated with poor outcomes. In addition, mesothelin expression, Lauren classification, and stage are meaningful predictive factors for peritoneal recurrence. Moreover, mesothelin was a significant predictor of a high risk of peritoneal recurrence in patients with stage III gastric cancer. Implications for Practice This study demonstrates that high mesothelin expression correlates with poor outcomes and is a significant predictor of peritoneal recurrence in patients with stage III gastric cancer. This study provides instrumental evidence for designing anti‐mesothelin antibody‐drug conjugate clinical trials in patients with diffuse‐type gastric cancer to reduce their high risk of peritoneal carcinomatosis.

This study introduces a data-driven approach for assessing the practices and effectiveness of digital diplomacy, using the cases of South Korea and Japan. The study compared the networking power of public diplomacy organizations based on social media use, engagement with the public, interaction patterns among the public, and public perceptions and attitudes toward organizations. This was accomplished through a three-step method employing social network analysis and topic modeling. The network analysis found that the Korean public diplomacy organization generated a larger, more loosely connected, and decentralized comment network than the Japanese organization, which presented a "small-world" connectivity pattern with highly interconnected actors. The findings also suggest that, compared to the Japanese organization, the Korean organization was successful in not only enhancing its soft power through social media but also building international networks among the foreign public.

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