1.High-Resolution Chromosomal Microarray with Diagnostic Potential for Detecting Exon-Level Copy Number Variations Using Targeted and Non-targeted Approaches
Yeseul KIM ; Jee-Soo LEE ; Boram KIM ; Man Jin KIM ; Sung Im CHO ; Seung Won CHAE ; Ho Seob SHIN ; Hoyeon LEE ; Ji Yeon KIM ; Moon-Woo SEONG
Annals of Laboratory Medicine 2026;46(2):190-199
Background:
Copy number variations (CNVs) play an important role in human genetic disorders. Detection of exon-level CNVs is crucial for accurate clinical diagnosis. The CytoScan XON Array, a high-resolution microarray, was recently developed to detect exonic CNVs of various genes.
Methods:
We evaluated the clinical performance of the CytoScan XON Array using 59 patient samples with previously identified CNVs, confirmed via methods including multiple ligation-dependent probe amplification (MLPA), gene-dose PCR, and mRNA assay. Concordance between CytoScan XON and orthogonal methods was evaluated in target regions, and diagnostic utility was compared with that of genome sequencing (GS)-based CNV calling tools through analysis of false-positive CNVs in non-target genomic regions.
Results:
For target regions, the CytoScan XON Array achieved concordance rates of 89.8% and 92.5% at the exon and gene levels, respectively, for all CNV calls. Concordance was higher for multi-exon CNVs (100%) than that for single-exon CNVs (82.6%, P = 0.03). For non-target regions, false-positive CNV calls were reduced to fewer than 0.01 per gene per person through filtering strategies. The array exhibited false-positive detection rates within dosage-sensitive genes comparable with those of GS-based tools.
Conclusions
The CytoScan XON Array, a reliable tool for detecting exon-level CNVs in target regions, can serve as a complementary approach to GS-based CNV calling tools for genome-wide CNV screening with high resolution. However, its performance for single-exon CNVs requires further optimization. Cross-validation with GS-based CNV calling tools is recommended to improve diagnostic accuracy.
2.Molecular Mosaics: Unveiling Heterogeneity in Synchronous Colorectal Cancers
Hyun Gu LEE ; Yeseul KIM ; Mi-Ju KIM ; Yeon Wook KIM ; Sun-Young JUN ; Deokhoon KIM ; In Ja PARK ; Seung-Mo HONG
Cancer Research and Treatment 2026;58(1):264-274
Purpose:
Molecular characteristics of synchronous colorectal cancers (SCRCs) remain incompletely elucidated, despite their importance in targeted therapy selection. We compared the molecular characteristics and somatic mutations between SCRCs.
Materials and Methods:
This retrospective study (2012-2014) included 98 consecutive patients with surgically resected SCRCs. Molecular characteristics, including microsatellite instability (MSI) and tumor-infiltrating lymphocytes (TILs), were analyzed for all cancer lesions. The intertumoral heterogeneity of SCRCs was evaluated using whole-exome sequencing (WES) for 18 cancers from nine patients with at least one MSI-high (MSI-H) tumor.
Results:
Twelve patients had at least one MSI-H tumor; five showed discordant MSI status. Mucinous adenocarcinoma frequency and TIL density were higher in patients with at least one MSI-H tumor than in those with only microsatellite-stable tumors. WES revealed that, except one patient (6.5%), most synchronous cancers shared few variants in each patient (0.09%-0.36%). The concordance rates for BRAF, KRAS, NRAS, and PIK3CA, in synchronous cancers from each patient were 66.7%, 66.7%, 66.7%, and 55.6%, respectively.
Conclusion
Although synchronous cancers shared a mutated gene, the mutation subtypes differed. SCRCs exhibited 5.1% MSI status discordance rate and a high discordance rate in somatic mutational variants. As intertumoral heterogeneity may affect the targeted therapy response, molecular analysis of all tumors is recommended for patients with SCRCs.
3.Assessing Trainee Needs for Developing Response Scenarios and Training Manuals for Unknown Infectious Diseases: Insights From a Focus Group Interview
Wooyoung JANG ; Jinnam KIM ; Dabin EOM ; Yeseul NA ; Choseok YOON ; Se Yoon PARK ; Bongyoung KIM
Journal of Korean Medical Science 2025;40(3):e81-
This study employed focus group interviews (FGIs) to evaluate the preparedness and training requirements for an emerging infectious disease response system in the Republic of Korea.Based on the FGIs, the critical role of interdepartmental cooperation in responding to emerging infectious diseases was identified, with agencies such as public health centers, police, and fire services playing key roles in scene control, decontamination, and patient transport. Frequent staff turnover and a lack of trained personnel at local government levels were significant challenges, necessitating the development of training materials for unskilled workers. Civil complaints, common during outbreaks, require public officials to be educated on legal frameworks and the management of patients’ rights. The absence of standardized procedures for managing patients, such as bed assignments considering underlying conditions and sample collection, underscores the need for comprehensive guidelines.Interviewees emphasized cross-departmental training, detailed manuals, and legal education to improve infectious disease response capabilities.
4.Stage Evaluation of Cystic Duct Cancer
Yeseul KIM ; You-Na SUNG ; Haesung JUNG ; Kyung Jin LEE ; Daegwang YOO ; Sun-Young JUN ; HyungJun CHO ; Shin HWANG ; Woohyung LEE ; Seung-Mo HONG
Cancer Research and Treatment 2025;57(2):528-538
Purpose:
Cystic duct cancers (CDCs) have been classified as extrahepatic bile duct cancers or gallbladder cancers (GBCs); however, it is unclear whether their clinical behavior is similar to that of distal extrahepatic bile duct cancers (DBDCs) or GBCs.
Materials and Methods:
T category of the CDCs was classified using current T category scheme of the GBCs and DBDCs, and clinicopathological factors were compared among 38 CDCs, 345 GBCs, and 349 DBDCs. We modified Nakata’s classifications (type 1, confined within cystic duct [CD]; combined types 2-4, extension beyond CD) and compared them.
Results:
No significant overall survival (OS) difference was observed between the patients with CDC, GBC, and DBDC. The T category of GBC staging was more accurate at distinguishing OS in patients with CDC than the DBDC staging. Patients with T3 CDC and GBC showed a significant OS difference when using the T category for GBC staging, while those with T1-T2 CDC and GBC showed no significant difference. In contrast, the T category of DBDC staging did not show any significant OS difference between patients with T1-T2 CDC and DBDC or T3 CDC and DBDC. Patients with type 1 CDC had significantly better OS than those with combined types.
Conclusion
Unlike GBCs and DBDCs, CDCs exhibit distinct clinicopathological characteristics. The OS is better when the CDC confines within the CD, compared to when it extends beyond it. Therefore, we propose a new T category scheme (T1, confined to CD; T2, invaded beyond CD) for better classifying CDCs.
5.Assessing Trainee Needs for Developing Response Scenarios and Training Manuals for Unknown Infectious Diseases: Insights From a Focus Group Interview
Wooyoung JANG ; Jinnam KIM ; Dabin EOM ; Yeseul NA ; Choseok YOON ; Se Yoon PARK ; Bongyoung KIM
Journal of Korean Medical Science 2025;40(3):e81-
This study employed focus group interviews (FGIs) to evaluate the preparedness and training requirements for an emerging infectious disease response system in the Republic of Korea.Based on the FGIs, the critical role of interdepartmental cooperation in responding to emerging infectious diseases was identified, with agencies such as public health centers, police, and fire services playing key roles in scene control, decontamination, and patient transport. Frequent staff turnover and a lack of trained personnel at local government levels were significant challenges, necessitating the development of training materials for unskilled workers. Civil complaints, common during outbreaks, require public officials to be educated on legal frameworks and the management of patients’ rights. The absence of standardized procedures for managing patients, such as bed assignments considering underlying conditions and sample collection, underscores the need for comprehensive guidelines.Interviewees emphasized cross-departmental training, detailed manuals, and legal education to improve infectious disease response capabilities.
6.Stage Evaluation of Cystic Duct Cancer
Yeseul KIM ; You-Na SUNG ; Haesung JUNG ; Kyung Jin LEE ; Daegwang YOO ; Sun-Young JUN ; HyungJun CHO ; Shin HWANG ; Woohyung LEE ; Seung-Mo HONG
Cancer Research and Treatment 2025;57(2):528-538
Purpose:
Cystic duct cancers (CDCs) have been classified as extrahepatic bile duct cancers or gallbladder cancers (GBCs); however, it is unclear whether their clinical behavior is similar to that of distal extrahepatic bile duct cancers (DBDCs) or GBCs.
Materials and Methods:
T category of the CDCs was classified using current T category scheme of the GBCs and DBDCs, and clinicopathological factors were compared among 38 CDCs, 345 GBCs, and 349 DBDCs. We modified Nakata’s classifications (type 1, confined within cystic duct [CD]; combined types 2-4, extension beyond CD) and compared them.
Results:
No significant overall survival (OS) difference was observed between the patients with CDC, GBC, and DBDC. The T category of GBC staging was more accurate at distinguishing OS in patients with CDC than the DBDC staging. Patients with T3 CDC and GBC showed a significant OS difference when using the T category for GBC staging, while those with T1-T2 CDC and GBC showed no significant difference. In contrast, the T category of DBDC staging did not show any significant OS difference between patients with T1-T2 CDC and DBDC or T3 CDC and DBDC. Patients with type 1 CDC had significantly better OS than those with combined types.
Conclusion
Unlike GBCs and DBDCs, CDCs exhibit distinct clinicopathological characteristics. The OS is better when the CDC confines within the CD, compared to when it extends beyond it. Therefore, we propose a new T category scheme (T1, confined to CD; T2, invaded beyond CD) for better classifying CDCs.
7.Assessing Trainee Needs for Developing Response Scenarios and Training Manuals for Unknown Infectious Diseases: Insights From a Focus Group Interview
Wooyoung JANG ; Jinnam KIM ; Dabin EOM ; Yeseul NA ; Choseok YOON ; Se Yoon PARK ; Bongyoung KIM
Journal of Korean Medical Science 2025;40(3):e81-
This study employed focus group interviews (FGIs) to evaluate the preparedness and training requirements for an emerging infectious disease response system in the Republic of Korea.Based on the FGIs, the critical role of interdepartmental cooperation in responding to emerging infectious diseases was identified, with agencies such as public health centers, police, and fire services playing key roles in scene control, decontamination, and patient transport. Frequent staff turnover and a lack of trained personnel at local government levels were significant challenges, necessitating the development of training materials for unskilled workers. Civil complaints, common during outbreaks, require public officials to be educated on legal frameworks and the management of patients’ rights. The absence of standardized procedures for managing patients, such as bed assignments considering underlying conditions and sample collection, underscores the need for comprehensive guidelines.Interviewees emphasized cross-departmental training, detailed manuals, and legal education to improve infectious disease response capabilities.
8.Assessing Trainee Needs for Developing Response Scenarios and Training Manuals for Unknown Infectious Diseases: Insights From a Focus Group Interview
Wooyoung JANG ; Jinnam KIM ; Dabin EOM ; Yeseul NA ; Choseok YOON ; Se Yoon PARK ; Bongyoung KIM
Journal of Korean Medical Science 2025;40(3):e81-
This study employed focus group interviews (FGIs) to evaluate the preparedness and training requirements for an emerging infectious disease response system in the Republic of Korea.Based on the FGIs, the critical role of interdepartmental cooperation in responding to emerging infectious diseases was identified, with agencies such as public health centers, police, and fire services playing key roles in scene control, decontamination, and patient transport. Frequent staff turnover and a lack of trained personnel at local government levels were significant challenges, necessitating the development of training materials for unskilled workers. Civil complaints, common during outbreaks, require public officials to be educated on legal frameworks and the management of patients’ rights. The absence of standardized procedures for managing patients, such as bed assignments considering underlying conditions and sample collection, underscores the need for comprehensive guidelines.Interviewees emphasized cross-departmental training, detailed manuals, and legal education to improve infectious disease response capabilities.
9.Stage Evaluation of Cystic Duct Cancer
Yeseul KIM ; You-Na SUNG ; Haesung JUNG ; Kyung Jin LEE ; Daegwang YOO ; Sun-Young JUN ; HyungJun CHO ; Shin HWANG ; Woohyung LEE ; Seung-Mo HONG
Cancer Research and Treatment 2025;57(2):528-538
Purpose:
Cystic duct cancers (CDCs) have been classified as extrahepatic bile duct cancers or gallbladder cancers (GBCs); however, it is unclear whether their clinical behavior is similar to that of distal extrahepatic bile duct cancers (DBDCs) or GBCs.
Materials and Methods:
T category of the CDCs was classified using current T category scheme of the GBCs and DBDCs, and clinicopathological factors were compared among 38 CDCs, 345 GBCs, and 349 DBDCs. We modified Nakata’s classifications (type 1, confined within cystic duct [CD]; combined types 2-4, extension beyond CD) and compared them.
Results:
No significant overall survival (OS) difference was observed between the patients with CDC, GBC, and DBDC. The T category of GBC staging was more accurate at distinguishing OS in patients with CDC than the DBDC staging. Patients with T3 CDC and GBC showed a significant OS difference when using the T category for GBC staging, while those with T1-T2 CDC and GBC showed no significant difference. In contrast, the T category of DBDC staging did not show any significant OS difference between patients with T1-T2 CDC and DBDC or T3 CDC and DBDC. Patients with type 1 CDC had significantly better OS than those with combined types.
Conclusion
Unlike GBCs and DBDCs, CDCs exhibit distinct clinicopathological characteristics. The OS is better when the CDC confines within the CD, compared to when it extends beyond it. Therefore, we propose a new T category scheme (T1, confined to CD; T2, invaded beyond CD) for better classifying CDCs.
10.Safety of the bivalent COVID-19 mRNA booster vaccination among persons aged over 18 years in the Republic of Korea
Seok-Kyoung CHOI ; Seontae KIM ; Mijeong KO ; Yeseul HEO ; Tae Eun KIM ; Yeonkyeong LEE ; Juyeon JANG ; Eunok BAHNG
Osong Public Health and Research Perspectives 2024;15(6):542-549
Objectives:
The aim of this study was to disseminate information about the safety of bivalent coronavirus disease 2019 (COVID-19) mRNA booster vaccines administered to adults in the Republic of Korea.
Methods:
Two databases were used to assess the safety of COVID-19 booster doses of Pfizer BA.1, Pfizer BA.4/5, Moderna BA.1, and Moderna BA.4/5 vaccines for adults aged 18 years and older.Adverse events (AEs) were analyzed using data reported to the web-based COVID-19 vaccination management system (CVMS) and a self-reported text-message survey.
Results:
Between October 11, 2022 and March 30, 2023, the CVMS received reports of 2,369 (93.7%) non-serious AEs from vaccinated adults, along with 158 (6.3%) serious AEs, which included 5 cases of anaphylaxis and 33 deaths. From October 11, 2022 to January 27, 2023, 40,022 people aged 18 and older responded to a survey conducted via text message. The booster doses were associated with fewer local and systemic AEs compared to the original vaccines. After receiving the bivalent vaccine, the most commonly reported AEs were pain at the injection site, headache, fatigue, and myalgia.
Conclusion
Overall, bivalent vaccines exhibited fewer AEs compared to the original vaccines. The majority of AEs were non-serious, and serious AEs were rare among adults aged 18 years and older following vaccination with the Pfizer and Moderna bivalent vaccines.

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