Kyung Un Choi

Pusan National University, Tsau-liang-hai, Busan, South Korea

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Publications (63)98.94 Total impact

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    ABSTRACT: Leiomyosarcoma of the uterus is an extremely rare but highly aggressive tumor that accounts for only 1–2 % of uterine malignancies, and is usually associated with a dismal outcome. Case presentation The authors present an unusual case of pedunculated subserosal leiomyosarcoma of the uterus mimicking ovarian carcinoma. A 57-year-old postmenopausal woman presented with progressive low abdominal pain and urinary frequency. Pelvic magnetic resonance imaging revealed a large adnexal mass with carcinomatosis peritonei. Laboratory examination revealed an elevated serum CA-125 level (398.4 U/ml). The patient underwent exploratory laparotomy under suspicion of ovarian malignancy. Frozen section indicated malignancy originating from the uterus, and thus, total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, pelvic and para-aortic lymph node dissection, and mass excision were performed. Subsequent histopathologic examination resulted in a final diagnosis of leiomyosarcoma of the uterus. The patient’s postoperative course was uneventful, and gemcitabine and docetaxel adjuvant chemotherapy was administered. The authors report an unusual case of pedunculated subserosal leiomyosarcoma of the uterus mimicking ovarian carcinoma.
    No preview · Article · Dec 2016 · Journal of Ovarian Research
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    ABSTRACT: Ovarian cancer shows high mortality due to development of resistance to chemotherapy and relapse. Cancer stem cells (CSCs) have been suggested to be a major contributor in developing drug resistance and relapse in ovarian cancer. In the present study, we isolated CSCs through sphere culture of A2780, SKOV3, OVCAR3 epithelial ovarian cancer cells and primary ovarian cancer cells from patients. We identified heat-stable factors secreted from ovarian CSCs stimulated migration and proliferation of CSCs. Mass spectrometry and ELISA analysis revealed that lysophosphatidic acid (LPA) was significantly elevated in CSC culture media compared with non-CSC culture media. Treatment of CSCs with LPA resulted in augmented CSC characteristics such as sphere-forming ability, resistance to anticancer drugs, tumorigenic potential in xenograft transplantation, and high expression of CSC-associated genes, including OCT4, SOX2, and aldehyde dehydrogenase 1. Treatment of CSCs with LPA receptor 1-specific inhibitors or silencing of LPA receptor 1 expression abrogated the LPA-stimulated CSC properties. Autotaxin, an LPA-producing enzyme, is highly secreted from ovarian CSCs, and pharmacological inhibition or knockdown of autotaxin markedly attenuated the LPA-producing, tumorigenic, and drug resistance potentials of CSCs. Clinicopathological analysis showed a significant survival disadvantage of patients with positive staining of autotaxin. In addition, we further identified that AKT1 activity was up-regulated in ovarian CSCs through an LPA-dependent mechanism and silencing of AKT1 expression led to suppression of CSC characteristics. These results suggest that autotaxin-LPA-LPA receptor 1-AKT1 signaling axis is critical for maintaining CSC characteristics through an autocrine loop and provide a novel therapeutic target for ovarian CSCs. This article is protected by copyright. All rights reserved.
    No preview · Article · Jan 2016 · Stem Cells
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    ABSTRACT: Tumor hypoxia is significant in promoting tumor progression and resistance to therapy, and hypoxia-inducible factor 1α (HIF-1α) is essential in the adaptive response of cells to hypoxia. The aim of the present study was to investigate the expression of hypoxic markers and evaluate their prognostic significance in soft tissue sarcoma (STS). A retrospective analysis of 55 patients with STS from Pusan National University Hospital (Busan, Korea) between 1998 and 2007 was conducted, using immunohistochemistry to analyze the expression of HIF-1α, carbonic anhydrase 9 (CA9), glucose transporter-1 (GLUT1) and vascular endothelial growth factor (VEGF). The association between the overexpression of these markers and clinicopathological characteristics, including the overall survival (OS) and progression-free survival (PFS) in cases of STS, were investigated. Overexpression of HIF-1α, CA9, GLUT1 and VEGF was shown in 54.5, 32.7, 52.7 and 25.5% of tumors, respectively, and all exhibited a significant association with high French Federation of Cancer Centers (FNCLCC) grade and high American Joint Committee on Cancer (AJCC) stage. Overexpression of HIF-1α and CA9 was associated with a shorter OS and a shorter PFS. On multivariate analysis, AJCC stage and HIF-1α overexpression had independent prognostic significance. In the group receiving chemotherapy (n=27), HIF-1α overexpression was independently associated with a decreased OS. These results indicate that overexpression of HIF-1α and CA9 is associated with poor prognosis, and that HIF-1α overexpression is an independent unfavorable prognostic factor in STS.
    Preview · Article · Apr 2015 · Oncology letters
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    ABSTRACT: In a viewpoint of histogenesis, lung adenocarcinoma can be subdivided into 2 groups, terminal respiratory unit (TRU) and non-TRU types. We recently reported a non-TRU type adenocarcinoma designated as ciliated adenocarcinoma (now, we prefer central type adenocarcinoma). We suggest reasons that mucinous adenocarcinoma should encompass central type adenocarcinoma to represent its biologic characteristics as non-TRU type adenocarcinoma. MUC5AC and MUC5B were more significantly expressed in non-TRU type adenocacinoma (P<0.01). Thirty-five (76.1%) and 45 cases (97.8%) of 46 non-TRU type adenocarcinoma showed positivity for MUC5AC and MUC5B. Twelve (7.6%) and eight (5.1%) cases of 157 TRU type adenocarainoma showed positivity for MUC5B and MUC5AC. NKX2-1 gene expression was measured with qRT-PCR. △△Ct of NKX2-1 gene expression was 6.79 for TRU type adenocarcinoma and 0.6 for non-TRU type adenocarcinoma. Overall survival and disease free survival were poorer in non-TRU type adenoarcinoma (P=0.02 and P=0.03). Multivariate test also showed non-TRU type adenocarcinoma is an independent prognostic factor (P=0.04). MUC5AC and MUC5B were specific makers for non-TRU adenocarcinoma including both of central type adenocarcinoma and mucinous adenocarcinoma. We suggest that non-TRU type adenocarcinoma presents poorer prognosis so that it should be regarded separately from TRU type adenocarcinoma. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    No preview · Article · Mar 2015 · Histopathology
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    ABSTRACT: Ovarian hemangiomas are usually of the cavernous type, and are rarely encountered. A 73-year-old woman presented with lower abdominal discomfort. Subsequent physical examination depicted a palpable mass in the lower abdomen. Abdominopelvic computed tomography (CT) revealed a well-circumscribed mass with thin septa measuring 12.1 × 9.0 cm in the right ovary. Levels of the tumor markers cancer antigen (CA)-125 and CA 19-9 were within the normal range. At laparoscopy, the tumor was found to be confined to the right ovary and to have a smooth surface. The final histopathological result was ovarian cavernous hemangioma. Microscopically, the mass consisted of multiple, dilated, blood-filled vascular channels separated by loose connective tissue, and all were lined by a single layer of flattened endothelium. The authors present a case of ovarian cavernous hemangioma presenting as a large growing mass in a postmenopausal woman and review previously published literature.
    Preview · Article · Jan 2015
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    ABSTRACT: Pure squamous cell carcinoma (SCC) of the stomach is rare and resembles SCC arising elsewhere in the body. The pathogenesis of SCC remains unclear and controversial. At present, <100 cases of primary SCC of the stomach have been reported. The current study presents a case of SCC of the stomach in a 61-year-old male. Total gastrectomy was performed and a 7.0×6.7×4.5-cm tumor with a superiorly located ulcer was identified in the cardia. Upon histological examination, a moderately-differentiated SCC was observed. Tumor cells extended to the serosa, and the perigastric regional lymph node was also involved. No evidence of human papillomavirus (HPV) or Epstein-Barr virus (EBV) infection was identified using a DNA microarray and in situ hybridization, respectively. A post-operative computed tomography scan four months after the gastrectomy revealed tumor recurrence and dissemination of the tumor to the jejunum and pancreas. The patient succumbed to the disease six months later despite the administration of low-dose adjuvant 5-fluorouracil/cisplatin chemotherapy.
    Preview · Article · Nov 2014 · Oncology letters
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    ABSTRACT: Background Epithelial-mesenchymal transition (EMT) is associated with tumor hypoxia. EMT is regulated, in part, by the action of TWIST, which inhibits of E-cadherin expression and may interfere with the p53 tumor-suppressor pathway. Methods We examined the expression of TWIST, E-cadherin, hypoxia-inducible factor 1α (HIF1α), and p53 by immunohistochemistry in 123 cases of ovarian epithelial cancers (OEC) to evaluate the role of TWIST in OEC. We assessed the association between protein expression and clinicopathologic parameters. Results The expression of TWIST, E-cadherin, HIF1α, and p53 proteins was found in 28.5%, 51.2%, 35.0%, and 29.3% of cases, respectively. TWIST expression was associated with higher histologic grade and unfavorable survival. TWIST expression was correlated with HIF1α expression and reduced E-cadherin expression. The altered HIF1α/TWIST/E-cadherin pathway was associated with lower overall survival (OS), while the co-expression of TWIST and p53 was correlated with lower progression-free survival. In the multivariate analyses, TWIST expression was an independent prognostic factor for OS. Conclusions Our data imply that TWIST expression could be a useful predictor of unfavorable prognosis for OEC. TWIST may affect the p53 tumor-suppressor pathway. Moreover, hypoxia-mediated EMT, which involves the HIF1α/TWIST/E-cadherin pathway may play an important role in the progression of OEC.
    Full-text · Article · Aug 2014 · The Korean Journal of Pathology
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    ABSTRACT: Background Soft tissue sarcomas (STS) are rare. We evaluated the WT1 protein expression level in various types of STS and elucidated the value of WT1 as a prognostic factor and a possible therapeutic target. Methods Immunohistochemical staining for WT1 was performed in 87 cases of STS using formalin-fixed, paraffin-embedded blocks. The correlation between WT1 expression and clinicopathological factors was analyzed. Survival analysis was conducted in 67 patients. We assessed the validity of WT1 immunohistochemistry as an index of WT1 protein expression using Western blot analysis. Results WT1 expression was noted in 47 cases (54.0%). Most rhabdomyosarcomas and malignant peripheral nerve sheath tumors showed WT1 expression (91.7% and 71.4%, respectively; P = 0.005). WT1 expression was related to higher FNCLCC histologic grade and AJCC tumor stage. In the group with high grade STS, strong WT1 expression was correlated with better survival (P = 0.025). The immunohistochemical results were correlated quantitatively with the staining score and the concentration of the Western blot band. Conclusions This study demonstrates that various types of STS show positive immunostaining for WT1 and that WT1 expression has a prognostic significance. So STS should be considered candidates for WT1 peptide--based immunotherapy.
    Full-text · Article · Jul 2014 · World Journal of Surgical Oncology
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    ABSTRACT: The S100A4 protein, a member of the S100 family of calcium-binding proteins, has been considered as a candidate prognostic marker in patients with cancer. The present study was conducted to evaluate the prognostic value of S100A4 and to examine its correlation with the clinicopathological parameters and the overall survival and progression-free survival in patients with endometrial carcinoma (EC). To do this, we performed immunohistochemistry of formalin-fixed tissue sections obtained from 135 cases of EC. In addition, we quantified the level of S100A4 mRNA using the quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). The cytoplasmic expression of S100A4 protein was observed in 35 cases (25.9%). There was a significant association between the expression of S100A4 and clinicopathological parameters such as histologic grade, FIGO stage, lymph node metastasis and loss of progesterone receptor (PR). qRT-PCR demonstrated that the level of S100A4 mRNA was significantly higher in ECs as compared with normal endometrium. The cytoplasmic expression of S100A4 had a significant correlation with shorter overall survival and progression-free survival on the Kaplan-Meyer survival analysis. In multivariate analysis, there was a significant correlation between S100A4 expression and a poorer OS. In conclusion, our results indicate that S100A4 may be a biological marker indicating the recurrence and poor prognosis in patients with EC.
    Preview · Article · Apr 2014 · Oncology Reports
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    ABSTRACT: Sparganosis is a parasitic infection caused by the plerocercoid tapeworm larva of the genus Spirometra. Although the destination of the larva is often a tissue or muscle in the chest, abdominal wall, extremities, eyes, brain, urinary tract, spinal canal, and scrotum, intramuscular sparganosis is uncommon and therefore is difficult to distinguish from a soft tissue tumor. We report a case of intramuscular sparganosis involving the gastrocnemius muscle in an elderly patient who was diagnosed using ultrasonography and MRI and treated by surgical excision. At approximately 1 cm near the schwannoma at the right distal sciatic nerve, several spargana worms were detected and removed.
    Full-text · Article · Feb 2014 · The Korean Journal of Parasitology
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    ABSTRACT: To diagnose soft tissue tumor, such as lipoma and Schwannoma, magnetic resonance imaging (MRI) is sufficient in most cases. However, various characteristics are found in MRI images of Schwannoma, thus other type of tumors are often misdiagnosed as Schwannoma with MRI images. In this study, we evaluate the diagnostic value of specific MRI findings of Schwannoma.
    Full-text · Article · Jan 2014
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    ABSTRACT: The aims of this article are to differentiate soft tissue masses showing low signal intensity on T2-weighted images (T2WIs) according to the histopathologic findings.
    Full-text · Article · Jan 2014
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    Hyun Sung Kim · Suk Kim · Kyungbin Kim · Kyung Un Choi · Joo Youn Kim
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    ABSTRACT: Myolipomas are very rare benign lipomatous soft tissue tumors which are usually located in retroperitoneum, abdominal and pelvic cavity, and the abdominal wall. They can be diagnosed histologically by the presence of irregularly admixed mature adipose tissue and smooth muscle fibers. The correct diagnosis of myolipoma is important, because it should be considered in the differential diagnosis of fat-containing lesions of the soft tissue and should follow a benign clinical course despite its frequently large size and deep location. We report here a case of myolipoma arising in the mesentery of the jejunum.
    Preview · Article · Dec 2013
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    ABSTRACT: Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory vascular disease that mainly affects renal, extracranial carotid, and vertebral arteries. Intracranial FMD is uncommon unlike extracranial or renal FMD, and the primary manifestation of intracranial FMD is intracranial aneurysm. We report an unusual case of intracranial FMD showing various ocular manifestations, including central retinal artery occlusion, transient monocular blindness, and oculomotor nerve palsy without renal involvement.
    No preview · Article · Dec 2013 · Journal of the neurological sciences
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    ABSTRACT: Abstract Polycomb group (PcG) genes are evolutionary conserved regulators of gene expression that contribute to normal lymphocyte development, and are involved in malignant transformation of these cells. Recently, BMI1 and EZH2 have been shown to be involved in lymphomagenesis and oncogenesis. We tried to elucidate EZH2 as a prognostic factor for diffuse large B cell lymphoma (DLBCL). High-level expression of EZH2 (EZH≥70%) was associated with superior overall survival (OS) of 85.8%, which compares to those of low expression (EZH2<70%) with OS of 44.5% (p=0.005). Subgroup analysis showed that the ABC subtype with high EZH2 expression had the highest overall survival (p= 0.011). In the analysis of EZH2 expression within the low IPI score, high EZH2 expression had a significant statistical correlation with longer OS (p=0.034). With high IPI scores, high EZH2 expression tended to be associated with longer OS (p=0.130). Our results showed that EZH2 expression had a high prognostic relevance to survival outcomes. We demonstrated that DLBCL was associated with increased expression of the EZH2 PcG protein and Ki67. The distribution of EZH2 expression was wider than that of Ki67. In summary, increased EZH2 expression of tumor cells was associated with improvements in overall survival.
    No preview · Article · Dec 2013 · Leukemia & lymphoma
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    ABSTRACT: Anticancer activity of silibinin, a flavonoid, has been demonstrated in various cancer cell types. However, the underlying mechanisms were not elucidated in human ovarian cancer cells. The present study was undertaken to examine the effect of silibinin in vitro and in vivo on tumor growth in human ovarian cancer cells. Silibinin decreased cell viability in a dose- and time-dependent manner. Silibinin caused an increase in reactive oxygen species (ROS) generation and the silibinin-induced cell death was prevented by the antioxidant N-acetylcysteine (NAC). Western blot analysis showed silibinin-induced down-regulation of extracellular signal-regulated kinase (ERK) and Akt. Transfection of constitutively active forms of MEK and Akt prevented the silibinin-induced cell death. Oral administration of silibinin in animals with subcutaneous A2780 cells reduced tumor volume. Subsequent tumor tissue analysis showed that silibinin treatment induced a decrease in Ki-67 positive cells, an increase in TUNEL-positive cells, activation of caspase-3, and inhibition of p-ERK and p-Akt. These results indicate that silibinin reduces tumor growth through inhibition of ERK and Akt in human ovarian cancer cells. These data suggest that silibinin may serve as a potential therapeutic agent for human ovarian cancers.
    Full-text · Article · Apr 2013 · Journal of Agricultural and Food Chemistry
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    ABSTRACT: Coronary artery embolism is an infrequent cause of acute myocardial infarction. In addition, native aortic valve thrombosis is a very rare condition. We report a case of native valve thrombosis causing acute ST-elevation myocardial infarction in healthy middle-aged man who has no established cardiovascular risk factor. We diagnosed native aortic valve thrombosis using various imaging techniques and confirmed our diagnosis histopathologically after surgical operation.
    No preview · Article · Jan 2013 · Cardiovascular pathology: the official journal of the Society for Cardiovascular Pathology
  • Young Don Kim · Seung Chul Kim · Kyung Un Choi · Eun Sook Jun
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    ABSTRACT: Abstract Objective: To determine whether the levels of inflammatory mediators in gastric fluid (GF) of a premature newborn are associated with those in amniotic fluid (AF) of the newborn's mother. Patients: Twenty-three pairs of pregnant women and their premature newborns <35 weeks gestation, born by Cesarean sections. Methods: Amniotic fluids and newborn gastric fluids were obtained from women during Cesarean section procedure. The mother-premature newborn dyads were retrospectively assessed to analyze the clinical and laboratory data. Concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-α) and mannose-binding lectin (MBL) were compared between amniotic and newborn gastric fluids in each dyad. Results: Premature newborns and their mother with funisitis had significantly higher median AF IL-6 and TNF-α and GF IL-8 concentrations than those without funisitis (p = 0.022 for AF IL-6; p = 0.023 for AF TNF-α; p = 0.022 for GF IL-8). The concentrations of IL-6, IL-8, TNF-α and MBL in newborn GF were significantly correlated with those in AF in each dyad (p = 0.000, r = 0.872 for IL-6; p = 0.000, r = 0.851 for IL-8; p = 0.000, r = 0.768 for TNF-α; p = 0.000, r = 0.845 for MBL, respectively). Conclusion: The levels of inflammatory mediators in GF of a premature newborn immediately after birth are strongly associated with those in AF of the newborn's mother.
    No preview · Article · Jan 2013 · The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians
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    ABSTRACT: Tumor hypoxia is associated with malignant progression and treatment resistance. Hypoxia-related factors, such as carbonic anhydrase IX (CA IX), glucose transporter-1 (GLUT-1), and vascular endothelial growth factor (VEGF) permit tumor cell adaptation to hypoxia. We attempted to elucidate the correlation of these markers with variable clinicopathological factors and overall prognosis. Immunohistochemistry for CA IX, GLUT-1, and VEGF was performed on formalin-fixed, paraffin-embedded tissues from 125 cases of ovarian epithelial cancer (OEC). CA IX expression was significantly associated with an endometrioid and mucinous histology, nuclear grade, tumor necrosis, and mitosis. GLUT-1 expression was associated with tumor necrosis and mitosis. VEGF expression was correlated only with disease recurrence. Expression of each marker was not significant in terms of overall survival in OECs; however, there was a significant correlation between poor overall survival rate and high coexpression of these markers. The present study suggests that it is questionable whether CA IX, GLUT-1, or VEGF can be used alone as independent prognostic factors in OECs. Using at least two markers helps to predict patient outcomes in total OECs. Moreover, the inhibition of two target gene combinations might prove to be a novel anticancer therapy.
    Full-text · Article · Dec 2012 · The Korean Journal of Pathology
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    ABSTRACT: Background and aimThe biologic behavior of gastrointestinal stromal tumors (GIST) is a topic of continuing controversy. The assessment of accurate mitotic figures is known to be one of the major indicators for patients with GIST. However, it is not always easy to search for mitotic figures (MFs) and count them accurately on hematoxylin and eosin stained (H&E) slides. Methods In this study, phopho-histone H3 (PHH3), which is a recently described specific mitosis marker, was immunohistochemically examined and compared to the mitotic count on H&E sections (H&E-MI) and Ki-67 expression (Ki-67 PI). A hundred cases of histologically confirmed GISTs were reviewed based on counting MF on H&E slides. PHH3 positive MFs (PHH3-MI) were counted in the same way, and the Ki-67 PI was calculated for each case. ResultsA strong correlation was found between PHH3-MI and H&E-MI. Recurrence-free survival was correlated with risk category by National Institutes of Health (NIH) consensus criteria (P = 0.017), mucosal invasion (P = 0.005), H&E-MI (P = 0.002), Ki-67 PI (P = 0.005), and PHH3-MI (P = 0.000). None of these factors was an independent prognostic factor. Conclusions Among GISTs, PHH3 staining was primarily found to support grading by facilitating mitotic counting, and it might have a prognostic value in GISTs.
    Preview · Article · Dec 2012 · Basic and Applied Pathology