Kyung Un Choi

Prof. Kyung Un Choi

Deparment of Pathology, Pusan National University

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 September 2017 in Scientific Reports
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Journal Article
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AKAhrong Kim
Ahrong Kim
SLSo Jeong Lee
So Jeong Lee
YKYoung Keum Kim
Young Keum Kim
WPWon Young Park
Won Young Park
DPDo Youn Park
Do Youn Park
KCKyung Un Choi
Kyung Un Choi
Immunotherapy targeting PD-1/PD-L1 axis showed benefits in cancer. Prognostic significance of tumour infiltrating lymphocytes (TILs) has been determined. We evaluated PD-L1 protein expression in tumour cells and TILs, PD-L1 mRNA level and various histopathologic factors including TILs using 167 formalin-fixed paraffin embedded tissues and 39 fresh tissue of HER2-positive breast cancer. TILs level and PD-L1 expression in tumour cells and TILs were significantly correlated one another. PD-L1 positivity in tumour cells was associated with high histologic grade and high TILs level (p < 0.001, both). High PD-L1 immunoscore in TILs and high total immunoscore (in tumour cells and TILs) of PD-L1 were correlated with high histologic grade (p = 0.001 and p < 0.001, respectively), absence of lymphovascular invasion (p = 0.012 and p = 0.007, respectively), negative hormone receptor expression (p = 0.044 and p = 0.001, respectively) and high TILs level (p < 0.001, both). High PD-L1 mRNA expression was associated with high TILs level (p < 0.001, both). PD-L1 positivity in tumour cells was associated with better disease-free survival in HR−/HER2+ breast cancer (p = 0.039). PD-L1 expression in tumour cells and TILs are significantly associated with TILs level in HER2-positive breast cancer. PD-L1 expression in tumour cells might be positive prognostic factor in HR−/HER2+ breast cancers.

17 September 2012 in World Journal of Surgical Oncology
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Journal Article
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KKKi Hyung Kim
Ki Hyung Kim
MJMoo Sung Jo
Moo Sung Jo
DSDong Soo Suh
Dong Soo Suh
MYMan Soo Yoon
Man Soo Yoon
DSDong Hun Shin
Dong Hun Shin
KCKyung Un Choi
Kyung Un Choi
Background: Toll-like receptors (TLR) are a family of pattern recognition receptors that constitutes a major part of the innate immune system. The TLR4/(Myeloid differentiation factor 88 (MyD88) signaling pathway has been shown to have oncogenic effects. Methods: To demonstrate the role of TLR4/MyD88 signaling in ovarian epithelial cancers (OECs), we examined the expression of TLR4, MyD88 and nuclear factor- κB (NF-κB) in OECs. The expression of TLR4, MyD88, and NF-κB was detected by immunohistochemistry, and the relationships between these and clinicopathologic features in 123 cases of OECs were also analyzed. Results: The expression of TLR4, MyD88, and NF-κB in OECs was observed in 46.3% (57/123), 36.6% (45/123) and 65% (80/123) of OEC cases, respectively. The TLR4, MyD88, and NF-κB expressions were associated with the histologic type of OECs, particularly with the clear cell type of OEC. There was no significant correlation between TLR4 or NF-κB expression and histologic grade, tumor size, mitotic count, FIGO (International Federation of Gynecology and Obstetrics) stage, disease recurrence. However, there was a significant correlation between MyD88 expression and FIGO stage, disease recurrence as well as histologic type. In univariate analysis, the expression of TLR4 and MyD88, and the coexpression of TLR4/MyD88 and TLR4/MyD88/NF-κB had a significant impact on the survival of patients with OECs. Only MyD88 expression had an independent prognostic significance in multivariate analysis. Conclusions: Our findings suggest that the TLR4/MyD88 signaling pathway is associated with the survival of patients with OECs, and that MyD88 is an independent prognostic predictor in patients with OECs. The TLR4/MyD88 signaling pathway may be a mechanism responsible for poor prognosis in patients with clear cell type of OEC.

28 January 2015 in Oncology Letters
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JKJeung Il Kim
Jeung Il Kim
KCKyung Un Choi
Kyung Un Choi
ILIn Sook Lee
In Sook Lee
YCYoung Jin Choi
Young Jin Choi
WKWon Tack Kim
Won Tack Kim
MSMee Young Sol
Mee Young Sol
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.

1 March 2019 in Oncology Letters
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CHChungsu Hwang
Chungsu Hwang
SLSo Jung Lee
So Jung Lee
JLJung Hee Lee
Jung Hee Lee
KKKi Hyung Kim
Ki Hyung Kim
DSDong Soo Suh
Dong Soo Suh
KCKyung Un Choi
Kyung Un Choi
Studies on tumor‑infiltrating lymphocytes (TILs) in epithelial ovarian cancer (EOC) have focused on the clinical significance of inflammatory cells of specific subtypes that are identifiable using immunohistochemistry. However, the subtypes of inflammatory cells that reportedly affect patient survival and prognosis have differed from study to study, and few studies have examined TILs using hematoxylin and eosin (H&E) staining. Therefore, the present study aimed to identify the clinical importance of general stromal TILs in EOC by using H&E staining to apply breast cancer recommendations from the International TILs Working Group 2014 on breast cancer using H&E staining. Stromal TILs in 256 EOC cases from Pusan National University Hospital and 475 cases of high‑grade serous carcinoma from The Cancer Genome Atlas dataset were assessed. Stromal TILs were evaluated using H&E‑stained slides according to the breast cancer recommendations of the International Working Group 2014, and patients were classified into low and high stromal TIL groups according to their stromal TIL values. The associations of these groups with clinicopathologic factors were assessed, and it was confirmed that group membership correlated with survival and prognosis. According to the χ2 assessment, the stromal TIL group was associated with tumor grade. Furthermore, the stromal TIL group was associated with overall survival according to Kaplan‑Meier analysis with the log‑rank test. Finally, the stromal TIL group was an independent prognostic factor according to univariate and multivariate Cox regression analyses. In cases of EOC, the evaluation of general stromal TILs on H&E‑stained slides could be used to predict prognosis.

Verified
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WYWookyeom Yang
Wookyeom Yang
DKDasol Kim
Dasol Kim
DKDae Kyoung Kim
Dae Kyoung Kim
KCKyung Un Choi
Kyung Un Choi
DSDong-Soo Suh
Dong-Soo Suh
JKJae Ho Kim
Jae Ho Kim
Ovarian cancer is a fatal gynecological malignancy. Although first-line chemotherapy and surgical operation are effective treatments for ovarian cancer, its clinical management remains a challenge owing to intrinsic or acquired drug resistance and relapse at local or distal lesions. Cancer stem cells (CSCs) are a small subpopulation of cells inside tumor tissues, and they can self-renew and differentiate. CSCs are responsible for the cancer malignancy involved in relapses as well as resistance to chemotherapy and radiation. These malignant properties of CSCs are regulated by cell surface receptors and intracellular pluripotency-associated factors triggered by internal or external stimuli from the tumor microenvironment. The malignancy of CSCs can be attenuated by individual or combined restraining of cell surface receptors and intracellular pluripotency-associated factors. Therefore, targeted therapy against CSCs is a feasible therapeutic tool against ovarian cancer. In this paper, we review the prominent roles of cell surface receptors and intracellular pluripotency-associated factors in mediating the stemness and malignancy of ovarian CSCs.

12 April 2017 in World Journal of Surgical Oncology
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Journal Article
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JLJung Hee Lee
Jung Hee Lee
DSDong Hoon Shin
Dong Hoon Shin
WPWon Young Park
Won Young Park
NSNari Shin
Nari Shin
AKAhrong Kim
Ahrong Kim
MSMee Young Sol
Mee Young Sol
Isocitrate dehydrogenase 1 (IDH1) mutation is common in low-grade glioma (approximately 80%) and acute myeloid leukemia (approximately 10%). Other than brain tumor or hematologic malignancies, intrahepatic cholangiocarcinoma (iCC) is a well-known solid tumor with IDH1 mutation (6.8–20%). Histologically, poor differentiation and clear cell change are associated with IDH1 mutation in iCC. Since hepatocellular carcinoma (HCC) shares histologic features with iCC, some specific subtypes of HCC might show a higher IDH1 mutation rate than reported before (0.5–1.5%). Forty-six cases of iCC and 48 cases of HCC (including 20 cases of clear cell type and 13 cases of pseudoglandular pattern) were tested for IDH1 mutation by pyrosequencing. Three cases in iCC (6.5%) and five cases in HCC (10.4%) had IDH1 mutation, all of which were Arg132Cys. IDH1 mutant HCCs were all clear cell type. Although the IDH1 mutation rate between iCC and HCC demonstrated no significant difference, clear cell HCC revealed statistically increased mutation rate compared to that of HCC without clear cell change (P = 0.009). Presence of IDH1 mutation was related with poor survival in clear cell HCC patients (P = 0.004). Clear cell HCC showed higher frequency of IDH1 mutation rate than other variants of HCC. This result consolidates the assumption that morphological features of tumors reflect molecular alterations.