1.Data-driven life-stage classification for companion dogs and cats using age-specific diagnosis patterns in South Korea
Jin-Young PARK ; Seogjin KANG ; Yoon Jung DO ; Eun-yeong BOK ; Jong Ryul PARK ; Tae Woo KIM ; Chang-Min LEE ; Woong-Bin RO ; Jang Yeop KIM ; Dong Yun LEE ; Heyong-Seok KIM ; Kyung-Duk MIN
Journal of Veterinary Science 2026;27(1):e5-
Objective:
To classify life stages for companion dogs and cats by identifying clusters in age-specific disease proportions derived from medical records, providing a data-driven foundation for health examination programs.
Methods:
We collected 505,667 medical records from 82 veterinary facilities in South Korea between 2020 and 2023. Diagnoses were standardized using GPT-4o and S-BioBERT. Following preprocessing, data from 27 facilities yielded 222,706 canine and 39,910 feline records for the final analysis. Principal component analysis and K-means clustering (K = 4) were applied to age-specific disease proportions to identify life stages.The 10 most highest-proportion diagnoses diseases were determined for each cluster.
Results:
Canine life stages were classified as ≤ 1 year, 2–5 years, 6–10 years, and 11–15+ years.Feline life stages were 1–2 years, 3–8 years, 9–12 years, and 13–15+ years. In dogs, developmental diseases were common in the youngest age group, while chronic diseases were more prevalent in older groups. In cats, oral and urinary diseases were high-ranking, conjunctivitis was most common in the early stage, and chronic diseases increased with age.
Conclusions
and Relevance: Age-specific diagnosis patterns support four practical life stages for dogs and cats in South Korea. These boundaries can inform evidence-based preventive examination schedules, animal health policy, and pet insurance product design.
2.Recurrence Dynamics of Pathological N2 Non–Small Cell Lung Cancer Based on IASLC Residual Tumor Descriptor
In Ha KIM ; Geun Dong LEE ; Sehoon CHOI ; Hyeong Ryul KIM ; Yong-Hee KIM ; Dong Kwan KIM ; Seung-Il PARK ; Jae Kwang YUN
Cancer Research and Treatment 2025;57(1):105-115
Purpose:
This study investigated the recurrence patterns and timing in patients with pathologic N2 (pN2) non-small cell lung cancer (NSCLC) according to the residual tumor (R) descriptor proposed by the International Association for the Study of Lung Cancer (IASLC).
Materials and Methods:
From 2004 to 2021, patients with pN2 NSCLC who underwent anatomical resection were analyzed according to the IASLC R criteria using medical records from a single center. Survival analysis was performed using Cox proportional hazards models. Recurrence patterns between complete (R0) and uncertain resections (R[un]) were compared.
Results:
In total, 1,373 patients were enrolled in this study: 576 (42.0%) in R0, 286 (20.8%) in R(un), and 511 (37.2%) in R1/R2 according to the IASLC R criteria. The most common reason for R(un) classification was positivity for the highest lymph node (88.8%). In multivariable analysis, the hazard ratios for recurrence in R(un) and R1/R2 compared to R0 were 1.18 (95% confidence interval [CI], 0.96–1.46) and 1.58 (1.31–1.90), respectively. The hazard rate curves displayed similar patterns among groups, peaking at approximately 12 months after surgery. There was a significant difference in distant recurrence patterns between R0 and R(un). Further analysis after stratification with the IASLC N2 descriptor showed significant differences in distant recurrence patterns between R0 and R(un) in patients pN2a1 and pN2a2 disease, but not in those with pN2b disease.
Conclusion
The IASLC R criteria has prognostic relevance in patients with pN2 NSCLC. R(un) is a highly heterogeneous group, and the involvement of the highest mediastinal lymph node can affect distant recurrence patterns.
3.Differences in the Prognostic Impact between Single-Zone and Multi-Zone N2 Node Metastasis in Patients with Station-Based Multiple N2 Non–Small Cell Lung Cancer
Shia KIM ; Geun Dong LEE ; SeHoon CHOI ; Hyeong Ryul KIM ; Yong-Hee KIM ; Dong Kwan KIM ; Seung-Il PARK ; Jae Kwang YUN
Cancer Research and Treatment 2025;57(1):95-104
Purpose:
The International Association for the Study of Lung Cancer suggests further subdivision of pathologic N (pN) category in non–small-cell lung cancer (NSCLC) by incorporating the location and number of involved lymph node (LN) stations. We reclassified patients with the station-based N2b disease into single-zone and multi-zone N2b groups and compared survival outcomes between the groups.
Materials and Methods:
This retrospective study included patients with pN2 NSCLC who underwent lobectomy from 2006 to 2019. The N2 disease was subdivided into four categories: single-station N2 without N1 (N2a1), single-station N2 with N1 (N2a2), multiple-station N2 with single zone involvement (single-zone N2b), and multiple-station N2 with multiple zone involvement (multi-zone N2b). LN zones included in the subdivision of N2 disease were upper mediastinal, lower mediastinal, aortopulmonary, and subcarinal.
Results:
Among 996 eligible patients, 211 (21.2%), 394 (39.6%), and 391 (39.3%) were confirmed to have pN2a1, pN2a2, and pN2b disease, respectively. In multivariable analysis after adjustment for sex, age, pT category, and adjuvant chemotherapy, overall survival was significantly better with single-zone N2b disease (n=125, 12.6%) than with multi-zone N2b disease (n=266, 26.7%) (hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.49 to 0.90; p=0.009) and was comparable to that of N2a2 disease (HR, 1.12; 95% CI, 0.83 to 1.49; p=0.46).
Conclusion
Prognosis of single-zone LN metastasis was better than that of multiple-zone LN metastasis in patients with N2b NSCLC. Along with the station-based N descriptors, zone-based descriptors might ensure optimal staging, enabling the most appropriate decision-making on adjuvant therapy for patients with pN2 NSCLC.
4.Preservation of ovarian function using human pluripotent stem cell-derived mesenchymal progenitor cells
Dong Ryul LEE ; Jeoung Eun LEE
Clinical and Experimental Reproductive Medicine 2025;52(1):30-37
Ovarian reserve diminishes with age, and older women experience a corresponding shift in sex hormone levels. These changes contribute to an age-dependent decrease in fertility and a decline in overall health. Furthermore, while survival rates following cancer treatment have improved for young female patients, a reduction in ovarian function due to the side effects of such treatments can be difficult to avoid. To date, no effective therapy has been recommended to preserve ovarian health in these patients. Mesenchymal progenitor cells (MPCs) are considered a promising option for cell therapy aimed at maintaining fertility and fecundity. Although MPCs derived from human adult tissues are recognized for their various protective effects against ovarian senescence, they are limited in quantity. Consequently, human pluripotent stem cell-derived MPCs (hPSC-MPCs), which exhibit high proliferative capacity and retain genetic stability during growth, have been utilized to delay reproductive aging. This review highlights the impact of hPSC-MPCs on preserving the functionality of damaged ovaries in female mouse models subjected to chemotherapy and natural aging. It also proposes their potential as a valuable cell source for fertility preservation in women with a variety of diseases.
5.Recurrence Dynamics of Pathological N2 Non–Small Cell Lung Cancer Based on IASLC Residual Tumor Descriptor
In Ha KIM ; Geun Dong LEE ; Sehoon CHOI ; Hyeong Ryul KIM ; Yong-Hee KIM ; Dong Kwan KIM ; Seung-Il PARK ; Jae Kwang YUN
Cancer Research and Treatment 2025;57(1):105-115
Purpose:
This study investigated the recurrence patterns and timing in patients with pathologic N2 (pN2) non-small cell lung cancer (NSCLC) according to the residual tumor (R) descriptor proposed by the International Association for the Study of Lung Cancer (IASLC).
Materials and Methods:
From 2004 to 2021, patients with pN2 NSCLC who underwent anatomical resection were analyzed according to the IASLC R criteria using medical records from a single center. Survival analysis was performed using Cox proportional hazards models. Recurrence patterns between complete (R0) and uncertain resections (R[un]) were compared.
Results:
In total, 1,373 patients were enrolled in this study: 576 (42.0%) in R0, 286 (20.8%) in R(un), and 511 (37.2%) in R1/R2 according to the IASLC R criteria. The most common reason for R(un) classification was positivity for the highest lymph node (88.8%). In multivariable analysis, the hazard ratios for recurrence in R(un) and R1/R2 compared to R0 were 1.18 (95% confidence interval [CI], 0.96–1.46) and 1.58 (1.31–1.90), respectively. The hazard rate curves displayed similar patterns among groups, peaking at approximately 12 months after surgery. There was a significant difference in distant recurrence patterns between R0 and R(un). Further analysis after stratification with the IASLC N2 descriptor showed significant differences in distant recurrence patterns between R0 and R(un) in patients pN2a1 and pN2a2 disease, but not in those with pN2b disease.
Conclusion
The IASLC R criteria has prognostic relevance in patients with pN2 NSCLC. R(un) is a highly heterogeneous group, and the involvement of the highest mediastinal lymph node can affect distant recurrence patterns.
6.Differences in the Prognostic Impact between Single-Zone and Multi-Zone N2 Node Metastasis in Patients with Station-Based Multiple N2 Non–Small Cell Lung Cancer
Shia KIM ; Geun Dong LEE ; SeHoon CHOI ; Hyeong Ryul KIM ; Yong-Hee KIM ; Dong Kwan KIM ; Seung-Il PARK ; Jae Kwang YUN
Cancer Research and Treatment 2025;57(1):95-104
Purpose:
The International Association for the Study of Lung Cancer suggests further subdivision of pathologic N (pN) category in non–small-cell lung cancer (NSCLC) by incorporating the location and number of involved lymph node (LN) stations. We reclassified patients with the station-based N2b disease into single-zone and multi-zone N2b groups and compared survival outcomes between the groups.
Materials and Methods:
This retrospective study included patients with pN2 NSCLC who underwent lobectomy from 2006 to 2019. The N2 disease was subdivided into four categories: single-station N2 without N1 (N2a1), single-station N2 with N1 (N2a2), multiple-station N2 with single zone involvement (single-zone N2b), and multiple-station N2 with multiple zone involvement (multi-zone N2b). LN zones included in the subdivision of N2 disease were upper mediastinal, lower mediastinal, aortopulmonary, and subcarinal.
Results:
Among 996 eligible patients, 211 (21.2%), 394 (39.6%), and 391 (39.3%) were confirmed to have pN2a1, pN2a2, and pN2b disease, respectively. In multivariable analysis after adjustment for sex, age, pT category, and adjuvant chemotherapy, overall survival was significantly better with single-zone N2b disease (n=125, 12.6%) than with multi-zone N2b disease (n=266, 26.7%) (hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.49 to 0.90; p=0.009) and was comparable to that of N2a2 disease (HR, 1.12; 95% CI, 0.83 to 1.49; p=0.46).
Conclusion
Prognosis of single-zone LN metastasis was better than that of multiple-zone LN metastasis in patients with N2b NSCLC. Along with the station-based N descriptors, zone-based descriptors might ensure optimal staging, enabling the most appropriate decision-making on adjuvant therapy for patients with pN2 NSCLC.
7.Preservation of ovarian function using human pluripotent stem cell-derived mesenchymal progenitor cells
Dong Ryul LEE ; Jeoung Eun LEE
Clinical and Experimental Reproductive Medicine 2025;52(1):30-37
Ovarian reserve diminishes with age, and older women experience a corresponding shift in sex hormone levels. These changes contribute to an age-dependent decrease in fertility and a decline in overall health. Furthermore, while survival rates following cancer treatment have improved for young female patients, a reduction in ovarian function due to the side effects of such treatments can be difficult to avoid. To date, no effective therapy has been recommended to preserve ovarian health in these patients. Mesenchymal progenitor cells (MPCs) are considered a promising option for cell therapy aimed at maintaining fertility and fecundity. Although MPCs derived from human adult tissues are recognized for their various protective effects against ovarian senescence, they are limited in quantity. Consequently, human pluripotent stem cell-derived MPCs (hPSC-MPCs), which exhibit high proliferative capacity and retain genetic stability during growth, have been utilized to delay reproductive aging. This review highlights the impact of hPSC-MPCs on preserving the functionality of damaged ovaries in female mouse models subjected to chemotherapy and natural aging. It also proposes their potential as a valuable cell source for fertility preservation in women with a variety of diseases.
8.Recurrence Dynamics of Pathological N2 Non–Small Cell Lung Cancer Based on IASLC Residual Tumor Descriptor
In Ha KIM ; Geun Dong LEE ; Sehoon CHOI ; Hyeong Ryul KIM ; Yong-Hee KIM ; Dong Kwan KIM ; Seung-Il PARK ; Jae Kwang YUN
Cancer Research and Treatment 2025;57(1):105-115
Purpose:
This study investigated the recurrence patterns and timing in patients with pathologic N2 (pN2) non-small cell lung cancer (NSCLC) according to the residual tumor (R) descriptor proposed by the International Association for the Study of Lung Cancer (IASLC).
Materials and Methods:
From 2004 to 2021, patients with pN2 NSCLC who underwent anatomical resection were analyzed according to the IASLC R criteria using medical records from a single center. Survival analysis was performed using Cox proportional hazards models. Recurrence patterns between complete (R0) and uncertain resections (R[un]) were compared.
Results:
In total, 1,373 patients were enrolled in this study: 576 (42.0%) in R0, 286 (20.8%) in R(un), and 511 (37.2%) in R1/R2 according to the IASLC R criteria. The most common reason for R(un) classification was positivity for the highest lymph node (88.8%). In multivariable analysis, the hazard ratios for recurrence in R(un) and R1/R2 compared to R0 were 1.18 (95% confidence interval [CI], 0.96–1.46) and 1.58 (1.31–1.90), respectively. The hazard rate curves displayed similar patterns among groups, peaking at approximately 12 months after surgery. There was a significant difference in distant recurrence patterns between R0 and R(un). Further analysis after stratification with the IASLC N2 descriptor showed significant differences in distant recurrence patterns between R0 and R(un) in patients pN2a1 and pN2a2 disease, but not in those with pN2b disease.
Conclusion
The IASLC R criteria has prognostic relevance in patients with pN2 NSCLC. R(un) is a highly heterogeneous group, and the involvement of the highest mediastinal lymph node can affect distant recurrence patterns.
9.Differences in the Prognostic Impact between Single-Zone and Multi-Zone N2 Node Metastasis in Patients with Station-Based Multiple N2 Non–Small Cell Lung Cancer
Shia KIM ; Geun Dong LEE ; SeHoon CHOI ; Hyeong Ryul KIM ; Yong-Hee KIM ; Dong Kwan KIM ; Seung-Il PARK ; Jae Kwang YUN
Cancer Research and Treatment 2025;57(1):95-104
Purpose:
The International Association for the Study of Lung Cancer suggests further subdivision of pathologic N (pN) category in non–small-cell lung cancer (NSCLC) by incorporating the location and number of involved lymph node (LN) stations. We reclassified patients with the station-based N2b disease into single-zone and multi-zone N2b groups and compared survival outcomes between the groups.
Materials and Methods:
This retrospective study included patients with pN2 NSCLC who underwent lobectomy from 2006 to 2019. The N2 disease was subdivided into four categories: single-station N2 without N1 (N2a1), single-station N2 with N1 (N2a2), multiple-station N2 with single zone involvement (single-zone N2b), and multiple-station N2 with multiple zone involvement (multi-zone N2b). LN zones included in the subdivision of N2 disease were upper mediastinal, lower mediastinal, aortopulmonary, and subcarinal.
Results:
Among 996 eligible patients, 211 (21.2%), 394 (39.6%), and 391 (39.3%) were confirmed to have pN2a1, pN2a2, and pN2b disease, respectively. In multivariable analysis after adjustment for sex, age, pT category, and adjuvant chemotherapy, overall survival was significantly better with single-zone N2b disease (n=125, 12.6%) than with multi-zone N2b disease (n=266, 26.7%) (hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.49 to 0.90; p=0.009) and was comparable to that of N2a2 disease (HR, 1.12; 95% CI, 0.83 to 1.49; p=0.46).
Conclusion
Prognosis of single-zone LN metastasis was better than that of multiple-zone LN metastasis in patients with N2b NSCLC. Along with the station-based N descriptors, zone-based descriptors might ensure optimal staging, enabling the most appropriate decision-making on adjuvant therapy for patients with pN2 NSCLC.
10.Preservation of ovarian function using human pluripotent stem cell-derived mesenchymal progenitor cells
Dong Ryul LEE ; Jeoung Eun LEE
Clinical and Experimental Reproductive Medicine 2025;52(1):30-37
Ovarian reserve diminishes with age, and older women experience a corresponding shift in sex hormone levels. These changes contribute to an age-dependent decrease in fertility and a decline in overall health. Furthermore, while survival rates following cancer treatment have improved for young female patients, a reduction in ovarian function due to the side effects of such treatments can be difficult to avoid. To date, no effective therapy has been recommended to preserve ovarian health in these patients. Mesenchymal progenitor cells (MPCs) are considered a promising option for cell therapy aimed at maintaining fertility and fecundity. Although MPCs derived from human adult tissues are recognized for their various protective effects against ovarian senescence, they are limited in quantity. Consequently, human pluripotent stem cell-derived MPCs (hPSC-MPCs), which exhibit high proliferative capacity and retain genetic stability during growth, have been utilized to delay reproductive aging. This review highlights the impact of hPSC-MPCs on preserving the functionality of damaged ovaries in female mouse models subjected to chemotherapy and natural aging. It also proposes their potential as a valuable cell source for fertility preservation in women with a variety of diseases.

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