Purpose: Extranodal natural killer/T-cell lymphoma (ENKTL) predominantly manifests in East Asia and Latin America. Despite shared intrinsic factors, such as ethnic and genetic backgrounds, the progression of ENKTL can be influenced by extrinsic factors related to changing lifestyle patterns. Materials and Methods: This study collected stool samples from newly diagnosed (ND)–ENKTL patients (n=40) and conducted whole genome shotgun sequencing. Results: ND-ENKTL revealed reduced alpha diversity in ND-ENKTL compared to healthy controls (HCs) (p=0.008), with Enterobacteriaceae abundance significantly contributing to the beta diversity difference between ENKTL and HCs (p < 0.001). Functional analysis indicated upregulated aerobic metabolism and degradation of aromatic compounds in ND-ENKTL. Enterobacteriaceae were associated not only with clinical data explaining disease status (serum C-reactive protein, stage, prognosis index of natural killer cell lymphoma [PINK], and PINK-E) but also with clinical outcomes (early relapse and short progression-free survival). The relative abundance of Enterobacteriaceae at the family level was similar between ENKTL and diffuse large B-cell lymphoma (DLBCL) (p=0.140). However, the ENKTL exhibited a higher abundance of Escherichia, in contrast to the prevalence of Enterobacter and Citrobacter in DLBCL. Linear regression analysis demonstrated a significant association between Escherichia abundance and programmed cell death-ligand-1 (PD-L1) levels in tissue samples (p=0.025), whereas no correlation with PD-L1 was observed for Enterobacteriaceae at the family level (p=0.571). Conclusion ND-ENKTL exhibited an abundance of Enterobacteriaceae and a dominant presence of Escherichia. These microbial characteristics correlated with disease status, treatment outcomes, and PD-L1 expression, suggesting the potential of the ENKTL microbiome as a biomarker and cause of lymphomagenesis, which warrants further exploration.

Purpose: Extranodal natural killer/T-cell lymphoma (ENKTL) predominantly manifests in East Asia and Latin America. Despite shared intrinsic factors, such as ethnic and genetic backgrounds, the progression of ENKTL can be influenced by extrinsic factors related to changing lifestyle patterns. Materials and Methods: This study collected stool samples from newly diagnosed (ND)–ENKTL patients (n=40) and conducted whole genome shotgun sequencing. Results: ND-ENKTL revealed reduced alpha diversity in ND-ENKTL compared to healthy controls (HCs) (p=0.008), with Enterobacteriaceae abundance significantly contributing to the beta diversity difference between ENKTL and HCs (p < 0.001). Functional analysis indicated upregulated aerobic metabolism and degradation of aromatic compounds in ND-ENKTL. Enterobacteriaceae were associated not only with clinical data explaining disease status (serum C-reactive protein, stage, prognosis index of natural killer cell lymphoma [PINK], and PINK-E) but also with clinical outcomes (early relapse and short progression-free survival). The relative abundance of Enterobacteriaceae at the family level was similar between ENKTL and diffuse large B-cell lymphoma (DLBCL) (p=0.140). However, the ENKTL exhibited a higher abundance of Escherichia, in contrast to the prevalence of Enterobacter and Citrobacter in DLBCL. Linear regression analysis demonstrated a significant association between Escherichia abundance and programmed cell death-ligand-1 (PD-L1) levels in tissue samples (p=0.025), whereas no correlation with PD-L1 was observed for Enterobacteriaceae at the family level (p=0.571). Conclusion ND-ENKTL exhibited an abundance of Enterobacteriaceae and a dominant presence of Escherichia. These microbial characteristics correlated with disease status, treatment outcomes, and PD-L1 expression, suggesting the potential of the ENKTL microbiome as a biomarker and cause of lymphomagenesis, which warrants further exploration.

Purpose: Extranodal natural killer/T-cell lymphoma (ENKTL) predominantly manifests in East Asia and Latin America. Despite shared intrinsic factors, such as ethnic and genetic backgrounds, the progression of ENKTL can be influenced by extrinsic factors related to changing lifestyle patterns. Materials and Methods: This study collected stool samples from newly diagnosed (ND)–ENKTL patients (n=40) and conducted whole genome shotgun sequencing. Results: ND-ENKTL revealed reduced alpha diversity in ND-ENKTL compared to healthy controls (HCs) (p=0.008), with Enterobacteriaceae abundance significantly contributing to the beta diversity difference between ENKTL and HCs (p < 0.001). Functional analysis indicated upregulated aerobic metabolism and degradation of aromatic compounds in ND-ENKTL. Enterobacteriaceae were associated not only with clinical data explaining disease status (serum C-reactive protein, stage, prognosis index of natural killer cell lymphoma [PINK], and PINK-E) but also with clinical outcomes (early relapse and short progression-free survival). The relative abundance of Enterobacteriaceae at the family level was similar between ENKTL and diffuse large B-cell lymphoma (DLBCL) (p=0.140). However, the ENKTL exhibited a higher abundance of Escherichia, in contrast to the prevalence of Enterobacter and Citrobacter in DLBCL. Linear regression analysis demonstrated a significant association between Escherichia abundance and programmed cell death-ligand-1 (PD-L1) levels in tissue samples (p=0.025), whereas no correlation with PD-L1 was observed for Enterobacteriaceae at the family level (p=0.571). Conclusion ND-ENKTL exhibited an abundance of Enterobacteriaceae and a dominant presence of Escherichia. These microbial characteristics correlated with disease status, treatment outcomes, and PD-L1 expression, suggesting the potential of the ENKTL microbiome as a biomarker and cause of lymphomagenesis, which warrants further exploration.

The increasing detection of papillary thyroid microcarcinoma (PTMC) has raised concerns about overtreatment.For low-risk PTMC, either immediate surgery or active surveillance (AS) can be considered. To support AS implementation, the Korean Thyroid Association convened a multidisciplinary panel and developed the first Korean guideline. AS is recommended to adults with pathologically proven Bethesda V-VI PTMC without clinical evidence of lymph node or distant metastasis, gross extrathyroidal extension, tracheal or recurrent laryngeal nerve invasion, or aggressive histology. Baseline assessment requires high‑resolution cervical ultrasound by experienced operators to rule out extrathyroidal extension, tracheal or recurrent laryngeal nerve invasion, and lymph node metastasis;contrast‑enhanced neck computed tomography is optional. Patient characteristics such as age, comorbidities, and capacity for long-term follow-up should be assessed. Shared decision-making should weigh the benefits and risks of surgery and AS, expected oncologic outcomes, complications, quality of life, anxiety, medical cost, and patient preference. Follow-up includes cervical ultrasound and thyroid function test every six months for two years, then annually. Disease progression, defined as significant tumor growth or newly detected nodal or distant metastasis, warrants surgery. Despite remaining uncertainties, this guideline offers a framework to ensure oncologic safety and support patient-centered active surveillance.

Purpose: This study investigated the occurrence of subsequent malignancies (SM) in adult patients with severe aplas‑ tic anemia (SAA) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) to address the lack of largescale, long-term data on this complication. Methods: A retrospective cohort analysis of 376 adult patients with SAA who underwent allo-HSCT between 2002 and 2021 at a single center was conducted. The incidence, risk factors, and survival impact of SM were also examined. Results: During the follow-up period, 31 cases of SM (8.2%) were identified. Approximately one-third (32.3%) of SM cases were hematologic malignancies, including post-transplant lymphoproliferative disorder (16.1%), myelodys‑ plastic neoplasm (6.5%), and acute myeloid leukemia (3.2%). Solid tumors accounted for 67.7% of cases, with thy‑ roid cancer being the most prevalent (25.8%). The 15-year cumulative incidence of SM was 11.2%, and the hazard ratio for overall survival according to the development of SM was 16.25 (p < 0.001). High-dose total body irradiation (TBI), anti-thymocyte globulin (ATG), and moderate-to-severe chronic graft-versus-host disease (GVHD) were identi‑ fied as significant risk factors for subsequent malignancy. Post-transplant SAA patients exhibited a 3.54-fold higher observed cancer incidence than the expected incidence calculated from the age-, sex-, and calendar year-matched general population. Conclusion SM is a significant long-term complication in patients with posttransplant SAA and has a substantial survival impact. Patients receiving high-dose TBI or ATG, and those with moderate-to-severe chronic GVHD, require vigilant long-term monitoring.

Background/Aims: Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by fat accumulation in the liver. MASLD encompasses both steatosis and MASH. Since MASH can lead to cirrhosis and liver cancer, steatosis and MASH must be distinguished during patient treatment. Here, we investigate the genomes, epigenomes, and transcriptomes of MASLD patients to identify signature gene set for more accurate tracking of MASLD progression. Methods: Biopsy-tissue and blood samples from patients with 134 MASLD, comprising 60 steatosis and 74 MASH patients were performed omics analysis. SVM learning algorithm were used to calculate most predictive features. Linear regression was applied to find signature gene set that distinguish the stage of MASLD and to validate their application into independent cohort of MASLD. Results: After performing WGS, WES, WGBS, and total RNA-seq on 134 biopsy samples from confirmed MASLD patients, we provided 1,955 MASLD-associated features, out of 3,176 somatic variant callings, 58 DMRs, and 1,393 DEGs that track MASLD progression. Then, we used a SVM learning algorithm to analyze the data and select the most predictive features. Using linear regression, we identified a signature gene set capable of differentiating the various stages of MASLD and verified it in different independent cohorts of MASLD and a liver cancer cohort. Conclusions We identified a signature gene set (i.e., CAPG, HYAL3, WIPI1, TREM2, SPP1, and RNASE6) with strong potential as a panel of diagnostic genes of MASLD-associated disease.

Purpose: This study investigated the occurrence of subsequent malignancies (SM) in adult patients with severe aplas‑ tic anemia (SAA) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) to address the lack of largescale, long-term data on this complication. Methods: A retrospective cohort analysis of 376 adult patients with SAA who underwent allo-HSCT between 2002 and 2021 at a single center was conducted. The incidence, risk factors, and survival impact of SM were also examined. Results: During the follow-up period, 31 cases of SM (8.2%) were identified. Approximately one-third (32.3%) of SM cases were hematologic malignancies, including post-transplant lymphoproliferative disorder (16.1%), myelodys‑ plastic neoplasm (6.5%), and acute myeloid leukemia (3.2%). Solid tumors accounted for 67.7% of cases, with thy‑ roid cancer being the most prevalent (25.8%). The 15-year cumulative incidence of SM was 11.2%, and the hazard ratio for overall survival according to the development of SM was 16.25 (p < 0.001). High-dose total body irradiation (TBI), anti-thymocyte globulin (ATG), and moderate-to-severe chronic graft-versus-host disease (GVHD) were identi‑ fied as significant risk factors for subsequent malignancy. Post-transplant SAA patients exhibited a 3.54-fold higher observed cancer incidence than the expected incidence calculated from the age-, sex-, and calendar year-matched general population. Conclusion SM is a significant long-term complication in patients with posttransplant SAA and has a substantial survival impact. Patients receiving high-dose TBI or ATG, and those with moderate-to-severe chronic GVHD, require vigilant long-term monitoring.

Purpose: This study investigated the occurrence of subsequent malignancies (SM) in adult patients with severe aplas‑ tic anemia (SAA) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) to address the lack of largescale, long-term data on this complication. Methods: A retrospective cohort analysis of 376 adult patients with SAA who underwent allo-HSCT between 2002 and 2021 at a single center was conducted. The incidence, risk factors, and survival impact of SM were also examined. Results: During the follow-up period, 31 cases of SM (8.2%) were identified. Approximately one-third (32.3%) of SM cases were hematologic malignancies, including post-transplant lymphoproliferative disorder (16.1%), myelodys‑ plastic neoplasm (6.5%), and acute myeloid leukemia (3.2%). Solid tumors accounted for 67.7% of cases, with thy‑ roid cancer being the most prevalent (25.8%). The 15-year cumulative incidence of SM was 11.2%, and the hazard ratio for overall survival according to the development of SM was 16.25 (p < 0.001). High-dose total body irradiation (TBI), anti-thymocyte globulin (ATG), and moderate-to-severe chronic graft-versus-host disease (GVHD) were identi‑ fied as significant risk factors for subsequent malignancy. Post-transplant SAA patients exhibited a 3.54-fold higher observed cancer incidence than the expected incidence calculated from the age-, sex-, and calendar year-matched general population. Conclusion SM is a significant long-term complication in patients with posttransplant SAA and has a substantial survival impact. Patients receiving high-dose TBI or ATG, and those with moderate-to-severe chronic GVHD, require vigilant long-term monitoring.

The American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging classification of thyroid cancer can predict death but cannot determine the type and frequency of follow-up testing. Risk stratification is a concept proposed by the American Thyroid Association that uses additional prognostic factors that are not included in the AJCC/UICC classification, such as number or size of metastatic lymph nodes, genetic mutations, and vascular invasion in follicular cancer, to further refine the prognosis of thyroid cancer. The risk of recurrence was categorized as low, intermediate, and high risk, and the need for total thyroidectomy, radioiodine therapy, or thyroid-stimulating hormone suppression was determined depending on each risk level. This approach has been accepted worldwide, and the previous recommendations of the Korean Thyroid Association followed a similar line of thinking but these have been modified in the revised 2024 guidelines.For the revised initial risk stratification, after careful review of the results of the recent meta-analyses and large observational studies and after a multidisciplinary meeting, four major changes were made: 1) thyroid cancer was reclassified according to the World Health Organization (WHO) 2022 tumor classification system; 2) recurrence risk was stratified by combining encapsulated follicular variant papillary thyroid cancer, follicular thyroid cancer, and oncocytic thyroid cancer, which have similar recurrence risk and associated factors, into follicular-patterned tumor; 3) low-risk groups were defined as those with a known recurrence rate of ≤5%, high-risk groups were upgraded to those with a known recurrence rate of ≥30%, and intermediate-risk groups were those with a recurrence risk of 5–30%; and 4) the intermediate risk group had the recurrence rate presented according to various clinicopathological factors, mainly based on reports from Korea. Thus, it is recommended to evaluate the initial risk group by predicting the recurrence rate by combining each clinical factor in individual patients, rather than applying the recurrence rate caused by single risk factor.