Tae Sung Ahn

Soonchunhyang University, Tenan, South Chungcheong, South Korea

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Publications (4)0 Total impact

  • Article: Expression of placenta growth factor in colorectal carcinomas.
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    ABSTRACT: Placenta growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family. PlGF is implicated in several pathologic processes, including the growth and spread of cancer and tumor angiogenesis. The aim of this study was to evaluate the expression and the clinical implications of PlGF in colorectal cancer. In order to ascertain the clinical significance of PlGF expression in colorectal cancer, the researcher analyzed the expression pattern of PlGF by using an immunohistochemical method and attempted to establish if a relationship existed between PlGF expression and microvessel density (MVD), and subsequently between PlGF expression and the predicted prognosis. A total of 83 patients with colorectal cancer were included for immunohistochemical staining. Clinicopathological characteristics were defined according to the tumor-node-metastasis (TNM) criteria of the Union for International Cancer Control. Clinicopathologic factors, such as age, sex, histological types of tumors, tumor cell grade, TNM stage, lymphovascular invasion, and lymph-node metastasis, were reviewed. In this study, the PlGF protein expression level was significantly correlated with MVD, patient survival, and clinicopathological factors such as lymph-node metastasis, TNM staging, lymphatic invasion and vascular invasion. PlGF may be an important angiogenic factor in human colorectal cancer, and in this study, PlGF expression level was significantly correlated with positive lymph-node metastases, tumor stage, and patient survival. These findings suggest that PlGF expression correlates with disease progression and may be used as a prognostic marker for colorectal cancer.
    Journal of the Korean Society of Coloproctology 12/2012; 28(6):315-20.
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    Article: Stromal-cell-derived Factor 1-α Promotes Tumor Progression in Colorectal Cancer.
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    ABSTRACT: Although stromal-cell-derived factor (SDF)-1α is suggested to be involved in tumorigenicity and tumor angiogenesis, the clinicopathological significance of its expression in colorectal cancers is not fully understood. We examined SDF-1α expression in colorectal cancers and investigated its relationship to clinicopathological features such as tumor staging, lymph-node metastasis, vascular invasion (VI), lymphatic invasion (LI) and neural invasion (NI). Specimens of 83 primary colorectal cancers were examined immunohistochemically, and the relationships between clinicopathological features and SDF-1α expression were analyzed. To compare the expressions between the normal colon tissue and colorectal cancer tissues, we performed Western blot analyses. According to the Western blot analyses, SDF-1α was more highly expressed in colorectal carcinoma tissues than in normal colonic mucosa (20/21). According to the immunohistochemical stain, SDF-1α was associated with nodal status, distant metastasis, tumor staging, VI and LI. SDF-1α expression had a significant prognostic value for overall survival. Kaplan-Meier plots of survival in patients with high SDF-1α showed that high SDF-1α expression was associated with a shorter overall survival. However, no association was found between SDF-1α expression and other pathologic or clinical variables, including age, gender, degree of differentiation, and presence of perineural invasion. The expression of SDF-1α might be associated with tumor progression in colorectal cancer. Inhibition of SDF-1α could be a therapeutic option in colorectal cancer patients.
    Journal of the Korean Society of Coloproctology 02/2012; 28(1):27-34.
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    Article: Correlation between Liver Metastases and the Level of PRL-3 mRNA Expression in Patients with Primary Colorectal Cancer.
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    ABSTRACT: Phosphatase of regenerating liver-3 (PRL-3) has been associated with metastasis promotion. However, clinical applications of this association have not yet been clearly demonstrated. In this study, we evaluated the relation of PRL-3 mRNA level in primary colorectal cancer to the corresponding stage and to other clinicopathologic factors. Two hundred forty-five patients with histologically-proven colorectal cancer underwent surgery between January 2004 and December 2006. RNA was extracted and cDNA was prepared by using reverse transcription. Quantification of PRL-3 was done using a real-time polymerase chain reaction. Eighty-six cases with well-preserved specimens were enrolled: 53 males and 33 females. The mean age was 63.4 years. According to tumour node metastasis (TNM) stage of the American Joint Committee on Cancer (AJCC), stage I was 11 cases, stage II was 38 cases, stage III was 23 cases, and stage IV was 14 cases. Among stage IV cases, one case was combined with liver and lung metastases, and one case was combined with liver metastases and peritoneal dissemination. The remaining stage IV patients were combined with only liver metastases. There was a significant correlation in PRL-3 mRNA expression between primary colorectal cancer and corresponding tumor stage. PRL-3 mRNA expression was increased in the liver metastases cases. Lymphatic and vascular invasion were significantly related with PRL-3 mRNA levels. Advanced stage prediction may be obtained by measuring the level of PRL-3 mRNA expression in primary colorectal cancer. Especially, the risk of liver metastases may be predicted by measuring the level of PRL-3 mRNA expression in primary colorectal cancer. Further study is required to confirm these preliminary results.
    Journal of the Korean Society of Coloproctology 10/2011; 27(5):231-6.
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    Article: Expression of the survivin-2B splice variant related to the progression of colorectal carcinoma.
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    ABSTRACT: Recently, two alternatively spliced survivin variants, survivin-ΔEx3 and survivin-2B, were identified in a single copy of the survivin gene. It has been reported that the expressions of survivin splice variants significantly correlates with the clinical results in many types of human carcinoma. We investigated the transcription levels of survivin and its splice variants in human colorectal carcinomas, and analyzed correlations between survivin expression levels and clinicopathologic features. We used Western blot and real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) to analyze the protein and mRNA expression levels of survivin variants in 51 colorectal carcinomas. The quantitative RT-PCR was performed using primer pairs specific for survivin and each of its splice variants, then normalized for the gene that encodes glyceraldehydes-3-phosphate dehydrogenase. In Western blotting, the protein levels of survivin were higher in the tumor tissue than in normal tissue. The expression of survivin, survivin-2B and survivin-ΔEx3 mRNA was present in 96%, 64.7%, and 82.4% of the samples, respectively. When the pathologic parameters were compared, colorectal cancers of advanced pT stages showed significant decrease in survivin-2B mRNA expression by the quantitative RT-PCR (P < 0.001). The decreased expression of survivin-2B might be related to tumor progression in colorectal cancers. This finding indicates that alternatively spliced variants of survivin may be involved in refining the functions of survivin during tumor progression.
    Journal of the Korean Surgical Society. 06/2011; 80(6):404-11.