Purpose: Advances in chemotherapeutic and targeted agents have increased pathologic complete response (pCR) rates after neoadjuvant systemic therapy (NST). Vacuum-assisted biopsy (VAB) has been suggested to accurately evaluate pCR. This study aims to confirm the non-inferiority of the 5-year disease-free survival of patients who omitted breast surgery when predicted to have a pCR based on breast magnetic resonance imaging (MRI) and VAB after NST, compared with patients with a pCR who had undergone breast surgery in previous studies. Methods The Omission of breast surgery for PredicTed pCR patients wIth MRI and vacuumassisted bIopsy in breaST cancer after neoadjuvant systemic therapy (OPTIMIST) trial is a prospective, multicenter, single-arm, non-inferiority study enrolling in 17 tertiary care hospitals in the Republic of Korea. Eligible patients must have a clip marker placed in the tumor and meet the MRI criteria suggesting complete clinical response (post-NST MRI size ≤ 1 cm and lesion-to-background signal enhancement ratio ≤ 1.6) after NST. Patients will undergo VAB, and breast surgery will be omitted for those with no residual tumor. Axillary surgery can also be omitted if the patient was clinically node-negative before and after NST and met the stringent criteria of MRI size ≤ 0.5 cm. Survival and efficacy outcomes are evaluated over five years.Discussion: This study seeks to establish evidence for the safe omission of breast surgery in exceptional responders to NST while minimizing patient burden. The trial will address concerns about potential undertreatment due to false-negative results and recurrence as well as improved patient-reported quality of life issues from the omission of surgery. Successful completion of this trial may reshape clinical practice for certain breast cancer subtypes and lead to a safe and less invasive approach for selected patients.

Background and Objectives: This clinical trial was conducted to evaluate the safety and efficacy of D+Storm™ drug-eluting stent (DES) and BioMatrix Flex™ DES. Methods: This study was a multicenter, subject-single-blind, randomized, and confirmed comparative clinical trial. According to the inclusion criteria, those diagnosed with stable angina, unstable angina, silent ischemia, or non-ST-segment myocardial infarction were selected among patients with coronary artery stenosis as subjects. Among the subjects with 50% stenosis on coronary angiography, the experiment was performed on those who had a lesion with reference vessel 2.5–4.0 mm in diameter and ≤40 mm in length. The primary endpoint was an in-segment late loss and the secondary endpoints were in-stent late lumen loss, stent malapposition, the incidence of mortality, myocardial infarction, reoperation, and stent thrombosis at 36 weeks. Results: 57 patients in the D+Storm™ DES group and 55 patients in the BioMatrix Flex™ DES group were enrolled in the study. Fifty-seven patients in the D+Storm™ DES group and Fifty-five patients in the BioMatrix Flex™ DES group were enrolled in the study. An average of in-segment late lumen loss was 0.08±0.13 mm in the D+Storm™ DES group and 0.14±0.32mm in the BioMatrix Flex™ DES group with no significant difference between the 2 groups (p=0.879). In addition, there was no significant difference in adverse events between D+Storm™ DES and BioMatrix Flex™ DES. Conclusions This study demonstrated the clinical effectiveness and safety of D+Storm™ DES implantation in patients with coronary artery disease over a 36-week follow-up period.

Background: Preconditioning with inflammatory stimuli is used to improve the secretion of anti-inflammatory agents in stem cells from variant species such as mouse, human, and dog. However, there are only few studies on feline stem cells. Objectives: This study aimed to evaluate the immune regulatory capacity of feline adipose tissue-derived (fAT) mesenchymal stem cells (MSCs) pretreated with interferon-gamma (IFN-γ). Methods: To assess the interaction of lymphocytes and macrophages with IFN-γ-pretreated fAT-MSCs, mouse splenocytes and RAW 264.7 cells were cultured with the conditioned media from IFN-γ-pretreated MSCs. Results: Pretreatment with IFN-γ increased the gene expression levels of cyclooxygenase-2, indoleamine 2,3-dioxygenase, hepatocyte growth factor, and transforming growth factorbeta 1 in the MSCs. The conditioned media from IFN-γ-pretreated MSCs increased the expression levels of M2 macrophage markers and regulatory T-cell markers compared to those in the conditioned media from naive MSCs. Further, prostaglandin E 2 (PGE 2 ) inhibitor NS-398 attenuated the immunoregulatory potential of MSCs, suggesting that the increased PGE 2 levels induced by IFN-γ stimulation is a crucial factor in the immune regulatory capacity of MSCs pretreated with IFN-γ. Conclusions IFN-γ pretreatment improves the immune regulatory profile of fAT-MSCs mainly via the secretion of PGE 2 , which induces macrophage polarization and increases regulatory T-cell numbers.

Background: Solar urticaria (SU) is a rare type of photodermatosis characterized by the appearance of itchy wheals and erythema within minutes after exposure to sunlight or artificial light. Only a few studies have analyzed the clinical and photobiological features of SU in Asia. Objective: We aimed to analyze the clinical and photobiological characteristics of SU. Methods: We retrospectively investigated the medical records of patients with SU who visited the Department of Dermatology at the Konkuk University Medical Center between January 2005 and October 2020. Results: Of the 52 patients, 43 (82.7%) were men, and 9 (17.3%) were women. The mean age at onset was 17.5 years (5∼47 years), and the mean threshold time was 21.2 minutes. Among the 36 patients who underwent phototesting, the action spectrum predominantly responsible for SU was ultraviolet (UV) A only in 14 (38.9%) patients and visible light (415 nm) only in nine (25.0%) patients. Three patients (8.3%) were induced by both UVA and visible light (415 nm). In eight (22.2%) patients, the symptoms were triggered only by natural sunlight. Serum immunoglobulin E (IgE) levels were measured in 39 patients, and 21 (53.8%) patients showed elevated IgE levels. Oral antihistamine (48.1%) was the most widely used treatment, followed by oral cyclosporine (15.4%) and phototherapy (11.5%). Conclusion SU is an uncommon type of photodermatosis in Korea, with a greater prevalence in men. In this study, UVA was found to be the predominant action spectrum responsible for SU.

Background: Pheochromocytoma and paraganglioma (PPGL) is diagnosed through biochemical confirmation of excessive catecholamines in urine and plasma. Recent technological developments have allowed us to measure urinary free metanephrines; however, the diagnostic accuracy of these new methods and the diagnostic cutoff values have not been evaluated. Methods: This is a retrospective study of 595 subjects, including 71 PPGL cases and 524 controls. PPGL was based on pathological confirmation. Subjects with no evidence of PPGL over 2 years were included in the control group. Results: Urinary free metanephrines yielded similar area under the curve (AUC) to urinary fractionated metanephrines and plasma free metanephrines. However, urinary free normetanephrine yielded a better AUC than did urinary fractionated normetanephrine. The optimal cutoff for urinary free metanephrine and normetanephrine corrected for urinary creatinine yielded 97.2% sensitivity and 98.1% specificity. Conclusion Urinary free metanephrines are a reliable method for diagnosing PPGL in Asian populations compared with existing biochemical methods.

Background: Preconditioning with inflammatory stimuli is used to improve the secretion of anti-inflammatory agents in stem cells from variant species such as mouse, human, and dog. However, there are only few studies on feline stem cells. Objectives: This study aimed to evaluate the immune regulatory capacity of feline adipose tissue-derived (fAT) mesenchymal stem cells (MSCs) pretreated with interferon-gamma (IFN-γ). Methods: To assess the interaction of lymphocytes and macrophages with IFN-γ-pretreated fAT-MSCs, mouse splenocytes and RAW 264.7 cells were cultured with the conditioned media from IFN-γ-pretreated MSCs. Results: Pretreatment with IFN-γ increased the gene expression levels of cyclooxygenase-2, indoleamine 2,3-dioxygenase, hepatocyte growth factor, and transforming growth factorbeta 1 in the MSCs. The conditioned media from IFN-γ-pretreated MSCs increased the expression levels of M2 macrophage markers and regulatory T-cell markers compared to those in the conditioned media from naive MSCs. Further, prostaglandin E 2 (PGE 2 ) inhibitor NS-398 attenuated the immunoregulatory potential of MSCs, suggesting that the increased PGE 2 levels induced by IFN-γ stimulation is a crucial factor in the immune regulatory capacity of MSCs pretreated with IFN-γ. Conclusions IFN-γ pretreatment improves the immune regulatory profile of fAT-MSCs mainly via the secretion of PGE 2 , which induces macrophage polarization and increases regulatory T-cell numbers.

Background: Solar urticaria (SU) is a rare type of photodermatosis characterized by the appearance of itchy wheals and erythema within minutes after exposure to sunlight or artificial light. Only a few studies have analyzed the clinical and photobiological features of SU in Asia. Objective: We aimed to analyze the clinical and photobiological characteristics of SU. Methods: We retrospectively investigated the medical records of patients with SU who visited the Department of Dermatology at the Konkuk University Medical Center between January 2005 and October 2020. Results: Of the 52 patients, 43 (82.7%) were men, and 9 (17.3%) were women. The mean age at onset was 17.5 years (5∼47 years), and the mean threshold time was 21.2 minutes. Among the 36 patients who underwent phototesting, the action spectrum predominantly responsible for SU was ultraviolet (UV) A only in 14 (38.9%) patients and visible light (415 nm) only in nine (25.0%) patients. Three patients (8.3%) were induced by both UVA and visible light (415 nm). In eight (22.2%) patients, the symptoms were triggered only by natural sunlight. Serum immunoglobulin E (IgE) levels were measured in 39 patients, and 21 (53.8%) patients showed elevated IgE levels. Oral antihistamine (48.1%) was the most widely used treatment, followed by oral cyclosporine (15.4%) and phototherapy (11.5%). Conclusion SU is an uncommon type of photodermatosis in Korea, with a greater prevalence in men. In this study, UVA was found to be the predominant action spectrum responsible for SU.

Purpose: In this trial, we investigated the efficacy and safety of adjuvant letrozole for hormone receptor (HR)-positive breast cancer. Here, we report the clinical outcome in postmenopausal women with HR-positive breast cancer treated with adjuvant letrozole according to estrogen receptor (ER) expression levels. Methods: In this multi-institutional, open-label, observational study, postmenopausal patients with HR-positive breast cancer received adjuvant letrozole (2.5 mg/daily) for 5 years unless they experienced disease progression or unacceptable toxicity or withdrew their consent. The patients were stratified into the following 3 groups according to ER expression levels using a modified Allred score (AS): low, intermediate, and high (AS 3–4, 5–6, and 7–8, respectively). ER expression was centrally reviewed. The primary objective was the 5-year disease-free survival (DFS) rate. Results: Between April 25, 2010, and February 5, 2014, 440 patients were enrolled. With a median follow-up of 62.0 months, the 5-year DFS rate in all patients was 94.2% (95% confidence interval [CI], 91.8–96.6). The 5-year DFS and recurrence-free survival (RFS) rates did not differ according to ER expression; the 5-year DFS rates were 94.3% and 94.1%in the low-to-intermediate and high expression groups, respectively (p = 0.6), and the corresponding 5-year RFS rates were 95.7% and 95.4%, respectively (p = 0.7). Furthermore, 25 patients discontinued letrozole because of drug toxicity. Conclusion Treatment with adjuvant letrozole showed very favorable treatment outcomes and good tolerability among Korean postmenopausal women with ER-positive breast cancer, independent of ER expression.