1.Prevalence of HER2-ultralow breast cancer in South Korea: a multicenter study by reassessment of HER2-zero cases
Min Chong KIM ; Eun Yoon CHO ; Hee Jin LEE ; Ji Shin LEE ; Jee Yeon KIM ; Wan Seop KIM ; Chungyeul KIM ; Sun-Young JUN ; Hye Jeong CHOI ; So Mang LEE ; Ahrong KIM ; Ji-Young KIM ; Jeong Yun SHIM ; Gyungyub GONG ; Young Kyung BAE
Journal of Pathology and Translational Medicine 2026;60(2):184-192
This study aimed to determine the prevalence of human epidermal growth factor receptor 2 (HER2)–ultralow breast cancer among cases initially classified as HER2 immunohistochemistry (IHC) 0 and assess interobserver variability in interpreting low-level HER2 expression. Methods: In this multicenter retrospective study, all invasive breast cancer cases diagnosed between January and December 2022 across 10 Korean institutions were retrieved. Institutional pathologists reexamined HER2 IHC slides originally reported as IHC 0 according to the 2018 American Society of Clinical Oncology/College of American Pathologists guidelines and reclassified them as HER2-null (0), HER2-ultralow (0+), or HER2-low (1+). Slides from 10% of HER2-null and HER2-ultralow cases were digitized for central review and independently assessed by two pathologists, with discrepancies resolved by consensus. Results: Among 8,026 cases, 2,836 cases (35.5%) were initially reported as IHC 0. Upon re-review, 1,673 (59.0%), 1,139 (40.2%), and 24 (0.8%) cases were reclassified as HER2-null, HER2-ultralow, and HER2-low, respectively. The prevalence of HER2-ultralow breast cancer varied considerably across institutions (23.7%–78.1%). Central review of 268 digitized cases showed concordance in 193 cases (72.0%). Among the 75 discordant cases, 54 tumors (72.0%) were upgraded from HER2-null to HER2-ultralow, and 18 (24.0%) tumors were upgraded from HER2-ultralow to HER2-low. Furthermore, two tumors (2.7%) were downgraded from HER2-ultralow to HER2-null. Conclusions: Approximately 40% of cases initially categorized as IHC 0 were reclassified as HER2-ultralow. The substantial inter-institutional variability observed in interpreting low-level HER2 expression highlights the need for standardized training and quality assurance to ensure accurate identification of patients eligible for HER2-targeted antibody–drug conjugates.
2.Introducing an Inclusive LGBTQ+ Medicine Curriculum: The Experience of Seoul National University College of Medicine
Korean Medical Education Review 2026;28(1):42-48
As sociocultural attitudes in South Korea continue to evolve, the growing visibility of lesbian, gay, bisexual, transgender, and queer (LGBTQ+) individuals highlights an increasing need for medical education that addresses diversity, equity, and inclusion (DEI). In response to this need, Seoul National University College of Medicine (SNUCM) introduced an LGBTQ+ medicine curriculum in 2021. The curriculum aims to prepare future physicians to provide equitable and respectful care to LGBTQ+ patients and to promote improvements in LGBTQ+ health through an affirming clinical approach. The program consists of both required and elective components. A required one-hour session for second-year medical students covers essential terminology, the historical process of depathologizing LGBTQ+ identities, and core principles of non-discriminatory and inclusive clinical care. Students seeking more advanced training may enroll in a four-week elective course, which provides in-depth learning through direct engagement with LGBTQ+ community members and site visits to LGBTQ+-affirming clinical settings. In addition, a ten-week research course is available to interested second-year students. Highly motivated senior-year students may further participate in a five-week advanced clinical placement focused on clinical observation and seminar-based learning. Participants reported high satisfaction with the program and perceived meaningful improvements in their competence in providing LGBTQ+-affirming health care. Broader national implementation of similar curricula will require coordinated collaboration among medical schools and relevant professional and expert organizations to establish shared core educational content and regionally structured clinical clerkship programs. The experience at SNUCM demonstrates both the necessity and the practical feasibility of integrating DEI-focused education, including LGBTQ+ medicine. Such efforts are expected to support the development of physicians who are committed to health equity and capable of delivering high quality, person-centered care free from prejudice.
3.NOVA1 Activation Modulates the Tumor Immune Microenvironment through STING Phosphorylation in Head and Neck Squamous Cell Carcinoma
Sehui KIM ; Hyang Mi KIM ; Jae Min BAE ; Sun Och YOON
Cancer Research and Treatment 2026;58(2):423-433
Purpose:
Neuro-oncological ventral antigen 1 (NOVA1), a neuron-specific pre-mRNA splicing factor, is involved in neuronal development and oncogenesis. NOVA1 overexpression is associated with favorable prognosis in head and neck squamous cell carcinoma (HNSCC) and gastric adenocarcinoma, whereas its downregulation correlates with poor outcomes. High NOVA1 levels in these cancers correlate with increased CD3+ and CD8+ T lymphocyte densities, suggesting involvement in tumor immune-inflammatory signals. This study explores NOVA1's role in regulating the immune-inflammatory cGAS-STING pathway in HNSCC cells and clinical tissues.
Materials and Methods:
HNSCC cell lines (FaDu, YD-10B, SNU-1066, and SNU-1076) were transfected with NOVA1 and poly(dA:dT). Quantitative real-time polymerase chain reaction and Western blot analysis were used to assess gene/protein expression. Enzymelinked immunosorbent assay quantified cytokine levels, and immunoprecipitation assessed protein interactions. Clinical tissue samples from 234 HNSCC patients were analyzed using immunohistochemistry to correlate NOVA1 and STING pathway markers with immune cell infiltration.
Results:
NOVA1 overexpression in HNSCC cells increased phosphorylation of STING (p-STING) without altering cGAS or TBK1. Immunoprecipitation showed an interaction between NOVA1 and p-STING. Overexpression of NOVA1, particularly with poly(dA:dT) treatment, tended to elevate CCL5 and CXCL10 expression. In clinical samples, NOVA1 expression strongly correlated with p-STING levels (r=0.749, p<0.001). Higher NOVA1 and p-STING expressions were linked to increased infiltration of CD3+ T cells, CD8+ T cells, and FOXP3+ regulatory T cells.
Conclusion
NOVA1 modulates the cGAS-STING pathway through STING phosphorylation and associated immune responses in HNSCC, providing a potential therapeutic target for enhancing anti-tumor immunity.
4.Detection Ability of Quality of Life Changes and Responsiveness of the KOQUSS-40 and the EORTC QLQ-C30/STO22 in Patients Who Underwent Gastrectomy: A Prospective Comparative Study
Bang Wool EOM ; Keun Won RYU ; Ji Yeong AN ; Yun-Suhk SUH ; In CHO ; Sung Geun KIM ; Ji-Ho PARK ; Hoon HUR ; Hyung-Ho KIM ; Sang-Hoon AHN ; Sun-Hwi HWANG ; Hong Man YOON ; Ki Bum PARK ; Hyoung-Il KIM ; In-Gyu KWON ; Han-Kwang YANG ; Byoung-Jo SUH ; Sang-Ho JEONG ; Tae-Han KIM ; Oh Kyoung KWON ; Hye-Seong AHN ; Ji Yeon PARK ; Ki Young YOON ; Myoung Won SON ; Seong-Ho KONG ; Young-Gil SON ; Geum Jong SONG ; Jong Hyuk YUN ; Jung-Min BAE ; Do Joong PARK ; Sol LEE ; Jun-Young YANG ; Kyung Won SEO ; You-Jin JANG ; So Hyun KANG ; Joongyub LEE ; Hyuk-Joon LEE ;
Cancer Research and Treatment 2026;58(1):221-231
Purpose:
The aim of this study is to compare the detection ability of quality of life (QoL) changes and responsiveness of the KOrean QUality of life in Stomach cancer patients Study group (KOQUSS)-40 and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ).
Materials and Methods:
A multicenter prospective observational study was conducted to evaluate QoL changes after various gastrectomies between January 2021 and April 2022. Participants were instructed to complete the KOQUSS-40 and EORTC QLQ-C30/STO22 preoperatively and at 1, 3, 6, and 12 months postoperatively. QoL changes over time and QoL responsiveness were assessed for each questionnaire.
Results:
Data from 491 patients who underwent curative gastrectomy for gastric cancer at 22 institutions were analyzed. The summary scores of the KOQUSS-40 and EORTC QLQ-STO22 showed significant differences between the total and proximal gastrectomy groups (p=0.044 and p=0.038, respectively), but no difference was observed for the EORTC QLQ-C30. Dysphagia on the KOQUSS-40 was significantly different between the total and proximal gastrectomy groups (p=0.031); however, dysphagia on the EORTC QLQ-STO22 did not differ. The responsiveness of the KOQUSS-40 was similar to that of the EORTC QLQ in patients who experienced ≥ 10% body weight loss, but approximately 10% less in patients receiving adjuvant chemotherapy than the EORTC QLQ.
Conclusion
KOQUSS-40 has several advantages over EORTC QLQ-C30/STO22 when comparing QoL between the total and proximal gastrectomy groups. The findings provide information for researchers investigating the QoL of patients who have undergone curative gastrectomy for gastric cancer.
5.Cervical Spinal Melanocytoma: A Case Report and Literature Review
Chan Joo PARK ; Soo Hyun LEE ; Do Heum YOON ; Seong Bae AN ; Inbo HAN ; Seung Hun SHEEN ; Sun-Yoon CHUNG ; Jinhyung HEO ; Hye Jeong CHOI ; Seil SOHN
The Nerve 2026;12(1):56-60
Spinal melanocytoma (SMC) is a rare, slow-growing tumor arising from melanocytes in the spinal cord. We report a patient with a cervical intra- and extradural spinal tumor causing progressive weakness and numbness. On magnetic resonance imaging (MRI), the lesion showed intense homogeneous enhancement, similar to that seen in common neurogenic spinal tumors. After complete resection, pathological examination confirmed melanocytoma. A review of previously reported cases identified 26 reports of this tumor in the cervical spine, most of which were treated with complete surgical resection. Gross total resection is the preferred treatment, although radiation therapy may be considered when residual tumor remains. We report a 25-year-old male patient who presented with progressive weakness and numbness in both the upper and lower extremities for 3 months. MRI showed homogeneous enhancement. The mass compressed the spinal cord at C6–7 and extended through the neural foramen. Based on the MRI findings, spinal schwannoma was suspected preoperatively. Surgical resection was performed with laminectomy, durotomy, and right facetectomy. A dark-colored mass with well-demarcated margins was exposed and removed. Postoperative MRI confirmed complete removal of the mass. The patient recovered well, and his preoperative myelopathic symptoms gradually improved. SMC is a rare benign tumor that may be mistaken for schwannoma. The treatment of choice is gross total resection.
6.Connective tissue disease is associated with the risk of posterior reversible encephalopathy syndrome following lung transplantation in Korea
Tae Jung KIM ; Hyun Joo LEE ; Samina PARK ; Sang-Bae KO ; Soo-Hyun PARK ; Seung Hwan YOON ; Kwon Joong NA ; In Kyu PARK ; Chang Hyun KANG ; Young Tae KIM ; Sun Mi CHOI ; Jimyung PARK ; Joong-Yub KIM ; Hong Yeul LEE
Acute and Critical Care 2025;40(1):79-86
Background:
Posterior reversible encephalopathy syndrome (PRES) is a rare complication of lung transplantation with poorly understood risk factors and clinical characteristics. This study aimed to examine the occurrence, risk factors, and clinical data of patients who developed PRES following lung transplantation.
Methods:
A retrospective analysis was conducted on 147 patients who underwent lung transplantation between February 2013 and December 2023. The patients were diagnosed with PRES based on the clinical symptoms and radiological findings. We compared the baseline characteristics and clinical information, including primary lung diseases and immunosuppressive therapy related to lung transplantation operations, between the PRES and non-PRES groups.
Results:
PRES manifested in 7.5% (n=11) of the patients who underwent lung transplantation, with a median onset of 15 days after operation. Seizures were identified as the predominant clinical manifestation (81.8%, n=9) in the group diagnosed with PRES. All patients diagnosed with PRES recovered fully. Patients with PRES were significantly associated with connective tissue disease-associated interstitial lung disease (45.5% vs. 18.4%, P=0.019, odds ratio=9.808; 95% CI, 1.064–90.386; P=0.044). Nonetheless, no significant variance was observed in the type of immunotherapy, such as the use of calcineurin inhibitors, blood pressure, or acute renal failure subsequent to lung transplantation.
Conclusions
PRES typically manifests shortly after lung transplantation, with seizures being the predominant initial symptom. The presence of preexisting connective tissue disease as the primary lung disease represents a significant risk factor for PRES following lung transplantation.
7.Primary Mucosa-Associated Lymphoid Tissue Lymphoma of the Breast with Synchronous Contralateral Invasive Breast Cancer:A Case Report
Kyeong Jin LEE ; Yoon Yeong CHOI ; Suk Jin CHOI ; Min Sun BAE
Journal of the Korean Society of Radiology 2025;86(2):272-278
Primary breast lymphoma is a rare malignant breast tumor, accounting for <1% of all breast cancers. Among them, diffuse large B-cell lymphoma is the most common histologic subtype.However, primary mucosa-associated lymphoid tissue (MALT) lymphoma is less common and more indolent than diffuse large B-cell lymphoma, and primary MALT lymphoma of the breast is extremely rare. We report a case of bilateral breast cancer in a 62-year-old woman with primary MALT lymphoma in right braest and contralateral invasive breast cancer in left breast. The patient presented with a palpable right breast lump, which appeared as a noncalcified mass on mammography and an indistinct irregular hypoechoic mass with internal vascularity on breast ultrasonography. The mass was pathologically confirmed by excisional biopsy as primary MALT lymphoma. The patient underwent dynamic contrast-enhanced breast MRI, which additionally detected a small suspicious mass in the left breast. This was a clinically and mammographically occult breast cancer diagnosed as invasive ductal carcinoma.
8.Implant–supported fixed prosthesis for orthognathic surgery in ectodermal dysplasia: a case report
Yeon-Ah SHIN ; Ji-Eun MOON ; Se-Ha KANG ; Chan-Ik PARK ; Yoon-Joo BAE ; Min-Seok OH ; Woo-Jin JEON ; Na-Ra KANG ; Min-Jung BAEK
The Journal of Korean Academy of Prosthodontics 2025;63(1):20-30
Patients with ectodermal dysplasia often have atrophied alveolar bone and an inadequate maxillomandibular relationship owing to congenital edentulism.Accurate implant placement that can overcomes anatomical limitations and orthognathic surgery to improve the maxillomandibular relationship is necessary for creating implant-supported prosthesis for these patients. Implant placement and provisional prosthesis fabrication before orthognathic surgery can provide critical fixed reference points and ensure accuracy during orthognathic surgery.In our patient, a digital system was used to design a surgical guide that considered the predictable position of the definitive prosthesis, allowing the placement of implants to overcome anatomical limitations and the creation of fixed reference points via the delivery of a provisional prosthesis for effective orthognathic surgery. The lack of compensation during orthognathic surgery was considered in the definitive prosthesis. As a result, a prosthesis with a minimal anterior cantilever was fabricated. This study aimed to determine the appropriate sequence of multidisciplinary collaborations that would, result in the best functional and aesthetic outcomes.
9.Evaluating Rituximab Failure Rates in Neuromyelitis Optica Spectrum Disorder: A Nationwide Real-World Study From South Korea
Su-Hyun KIM ; Ju-Hong MIN ; Sung-Min KIM ; Eun-Jae LEE ; Young-Min LIM ; Ha Young SHIN ; Young Nam KWON ; Eunhee SOHN ; Sooyoung KIM ; Min Su PARK ; Tai-Seung NAM ; Byeol-A YOON ; Jong Kuk KIM ; Kyong Jin SHIN ; Yoo Hwan KIM ; Jin Myoung SEOK ; Jeong Bin BONG ; Sohyeon KIM ; Hung Youl SEOK ; Sun-Young OH ; Ohyun KWON ; Sunyoung KIM ; Sukyoon LEE ; Nam-Hee KIM ; Eun Bin CHO ; Sa-Yoon KANG ; Seong-il OH ; Jong Seok BAE ; Suk-Won AHN ; Ki Hoon KIM ; You-Ri KANG ; Woohee JU ; Seung Ho CHOO ; Yeon Hak CHUNG ; Jae-Won HYUN ; Ho Jin KIM
Journal of Clinical Neurology 2025;21(2):131-136
Background:
and Purpose Treatments for neuromyelitis optica spectrum disorder (NMOSD) such as eculizumab, ravulizumab, satralizumab, and inebilizumab have significantly advanced relapse prevention, but they remain expensive. Rituximab is an off-label yet popular alternative that offers a cost-effective solution, but its real-world efficacy needs better quantification for guiding the application of newer approved NMOSD treatments (ANTs). This study aimed to determine real-world rituximab failure rates to anticipate the demand for ANTs and aid in resource allocation.
Methods:
We conducted a nationwide retrospective study involving 605 aquaporin-4-antibody-positive NMOSD patients from 22 centers in South Korea that assessed the efficacy and safety of rituximab over a median follow-up of 47 months.
Results:
The 605 patients treated with rituximab included 525 (87%) who received continuous therapy throughout the follow-up period (median=47 months, interquartile range=15–87 months). During this period, 117 patients (19%) experienced at least 1 relapse. Notably, 68 of these patients (11% of the total cohort) experienced multiple relapses or at least 1 severe relapse.Additionally, 2% of the patients discontinued rituximab due to adverse events, which included severe infusion reactions, neutropenia, and infections.
Conclusions
This study has confirmed the efficacy of rituximab in treating NMOSD, as evidenced by an 87% continuation rate among patients over a 4-year follow-up period. Nevertheless, the occurrence of at least one relapse in 19% of the cohort, including 11% who experienced multiple or severe relapses, and a 2% discontinuation rate due to adverse events highlight the urgent need for alternative therapeutic options.
10.Prospective Multicenter Observational Study on Postoperative Quality of Life According to Type of Gastrectomy for Gastric Cancer
Sung Eun OH ; Yun-Suhk SUH ; Ji Yeong AN ; Keun Won RYU ; In CHO ; Sung Geun KIM ; Ji-Ho PARK ; Hoon HUR ; Hyung-Ho KIM ; Sang-Hoon AHN ; Sun-Hwi HWANG ; Hong Man YOON ; Ki Bum PARK ; Hyoung-Il KIM ; In Gyu KWON ; Han-Kwang YANG ; Byoung-Jo SUH ; Sang-Ho JEONG ; Tae-Han KIM ; Oh Kyoung KWON ; Hye Seong AHN ; Ji Yeon PARK ; Ki Young YOON ; Myoung Won SON ; Seong-Ho KONG ; Young-Gil SON ; Geum Jong SONG ; Jong Hyuk YUN ; Jung-Min BAE ; Do Joong PARK ; Sol LEE ; Jun-Young YANG ; Kyung Won SEO ; You-Jin JANG ; So Hyun KANG ; Bang Wool EOM ; Joongyub LEE ; Hyuk-Joon LEE ;
Journal of Gastric Cancer 2025;25(2):382-399
Purpose:
This study evaluated the postoperative quality of life (QoL) after various types of gastrectomy for gastric cancer.
Materials and Methods:
A multicenter prospective observational study was conducted in Korea using the Korean Quality of Life in Stomach Cancer Patients Study (KOQUSS)-40, a new QoL assessment tool focusing on postgastrectomy syndrome. Overall, 496 patients with gastric cancer were enrolled, and QoL was assessed at 5 time points: preoperatively and at 1, 3, 6, and 12 months after surgery.
Results:
Distal gastrectomy (DG) and pylorus-preserving gastrectomy (PPG) showed significantly better outcomes than total gastrectomy (TG) and proximal gastrectomy (PG) with regard to total score, indigestion, and dysphagia. DG, PPG, and TG also showed significantly better outcomes than PG in terms of dumping syndrome and worry about cancer. Postoperative QoL did not differ significantly according to anastomosis type in DG, except for Billroth I anastomosis, which achieved better bowel habit change scores than the others. No domains differed significantly when comparing double tract reconstruction and esophagogastrostomy after PG. The total QoL score correlated significantly with postoperative body weight loss (more than 10%) and extent of resection (P<0.05 for both).Reflux as assessed by KOQUSS-40 did not correlate significantly with reflux observed on gastroscopy 1 year postoperatively (P=0.064).
Conclusions
Our prospective observation using KOQUSS-40 revealed that DG and PPG lead to better QoL than TG and PG. Further study is needed to compare postoperative QoL according to anastomosis type in DG and PG.

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