• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.391-393
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• 2011

본 연구에서는 원자력 발전 및 화력 발전소에서 Turbine 운전 시 열교환기 및 콘덴서에 증기를 응축시 열효율을 높여주기 위해 콘덴서 Tube 내에 이물질 및 스케일을 Sponge Ball을 이용하여 자동으로 제거하는 장치로서 콘덴서 튜브 클리닝 시스템(CTCS)에 사용되고 있는 Screen 재료인 Duplex Stainless Steel UNS S31803의 파손사례에 대해 연구하였다. 파손원인 분석은 스크린의 강도해석, 재료의 화학분석시험, 조직시험 및 점용접부의 신뢰성 시험(Peel-off test)으로 수행되었고 저항용접부의 용접 불량 때문에 발생하였을 확인하였다.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.6
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• pp.521-525
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• 2014

Circulating tumor cells (CTCs) in the bloodstream of cancer patients provide an accessible source for detection, characterization, and monitoring of nonhematological cancers. The effectiveness of the CTC-Chip for the isolation of ovarian cancer cells was demonstrated by adapting the herringbone-chip (HB-Chip). The motions of the particles on the HB chip were simulated by a unique combination of buoyant, gravitational forces, and helical flows with a computational modeling. The motions of cells are demonstrated by applying polystylene bead and ovarian cancer cells into the microfabricated HB-Chip. The experimental results from beads and cells are well accordance with the simulated ones, as previously reported by Toner group. Thus, I expect that these modeling and experimental skills will play key roles in the clinical applications on CTC isolation as well as the basic research on characterization of CTCs under flow.

• Journal of Digestive Cancer Research
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• v.8 no.1
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• pp.56-60
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• 2020

In recent years, liquid biopsy has received immense attention. Liquid biopsy is a minimally invasive method used for obtaining biological fluids including urine, pleural fluid and, mostly, peripheral blood. Liquid biopsy involves various targets including circulating tumors cells (CTCs), circulating cell-free tumor DNA (ctDNA), and microRNA (miRNA). Colorectal cancer (CRC), like other solid tumors, shed tumor cells into the bloodstream. Analysis of these CTCs, as well as ctDNA is the primary objective of the liquid biopsy. Evaluation of CTC or ctDNA offers information about early tumor release, development of tumor metastasis and also about mechanisms involved in tumor resistance to treatment.

• Tuberculosis and Respiratory Diseases
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• v.83 no.1
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• pp.61-70
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• 2020

Background: Circulating tumor cells (CTCs) are frequently detected in patients with advanced-stage malignant tumors and could act as a predictor of poor prognosis. However, there is a paucity of data on the relationship between CTC number and primary tumor volume in patients with lung cancer. Therefore, our study aimed to evaluate the relationship between CTC number and primary tumor volume in patients with lung adenocarcinoma. Methods: We collected blood samples from 21 patients with treatment-naive lung adenocarcinoma and 73 healthy individuals. To count CTCs, we used a CTC enrichment method based on fluid-assisted separation technology. We compared CTC numbers between lung adenocarcinoma patients and healthy individuals using propensity score matching, and performed linear regression analysis to analyze the relationship between CTC number and primary tumor volume in lung adenocarcinoma patients. Results: CTC positivity was significantly more common in lung adenocarcinoma patients than in healthy individuals (p<0.001). The median primary tumor volume in CTC-negative and CTC-positive patients was 10.0 ㎤ and 64.8 ㎤, respectively. Multiple linear regression analysis showed that the number of CTCs correlated with primary tumor volume in lung adenocarcinoma patients (β=0.903, p=0.002). Further subgroup analysis showed a correlation between CTC number and primary tumor volume in patients with distant (p=0.024) and extra-thoracic (p=0.033) metastasis (not in patients with distant metastasis). Conclusion: Our study showed that CTC numbers may be associated with primary tumor volume in lung adenocarcinomas patients, especially in those with distant metastasis.

• Journal of Chest Surgery
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• v.50 no.2
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• pp.126-129
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• 2017

The identification of circulating tumor cells (CTCs) is clinically important for diagnosing cancer. We have previously developed a size-based filtration platform followed by epithelial cell adhesion molecule immunofluorescence staining for detecting CTCs. To characterize CTCs independently of cell surface protein expression, we incorporated a chromosomal fluorescence in situ hybridization (FISH) assay to detect abnormal copy numbers of chromosomes in cells collected from peripheral blood samples by the size-based filtration platform. Aneuploid cells were detected in the peripheral blood of patients with lung cancer. Unexpectedly, aneuploid cells were also detected in the control group, which consisted of peripheral blood samples from patients with benign lung diseases, such as empyema necessitatis and non-tuberculous mycobacterial lung disease. These findings suggest that chromosomal abnormalities are observed not only in tumor cells, but also in benign infectious diseases. Thus, our findings present new considerations and bring into light the possibility of false positives when using FISH for cancer diagnosis.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6015-6020
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• 2014

Background: Isolation and characterization of circulating tumor cells (CTCs) in patients suffering from a variety of different cancers have become hot biomarker topics. In this study, we evaluated the prognostic value of CTCs in pancreatic cancer. Materials and Methods: Initial literature was identified using Medline and EMBASE. The primary data were hazard ratios (HRs) with 95% confidence intervals (CIs) of survival outcomes, including overall survival (OS) and progression free survival/recurrence free survival (PFS/RFS). Results: A total of 9 eligible studies were included in this meta-analysis, published between 2002 and 2013. The estimated pooled HR and 95%CI for OS for all studies was 1.64 (95%CI 1.39-1.94, p<0.00001) and the pooled HR and 95%CI for RFS/DFS was 2.36 (95%CI 1.41-3.96, p<0.00001). The HRs and 95%CIs for OS and RFS/DFS in patients before treatment were 1.93 (95%CI 1.26-2.96, p=0.003) and 1.82 (95%CI 1.22-2.72, p=0.003), respectively. In patients receiving treatment, the HRs and 95%CI for OS and RFS/DFS were 1.37 (95%CI 1.00-1.86, p=0.05) and 1.89 (95%CI 1.01-3.51, p=0.05), respectively. Moreover, the pooled HR and 95%CI for OS in the post-treatment group was 2.20 (95%CI 0.80-6.02, p=0.13) and the pooled HR for RFS/DFS was 8.36 (95%CI 3.22-21.67, p<0.0001). Conclusions: The meta-analysis provided strong evidence supporting the proposition that CTCs detected in peripheral blood have a fine predictive role in pancreatic patients especially on the time point of post-treatment.

• The Korean journal of helicobacter and upper gastrointestinal research
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• v.18 no.3
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• pp.157-161
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• 2018

Liquid biopsy, the analysis of circulating biomarkers from peripheral blood, such as circulating tumor cells (CTCs) and circulating tumor DNA, and exosomes, offers a less invasive, new source of cancer-derived materials that may reflect the status of the disease better and thereby contribute to personalized treatment. Recent advances in microfluidics and molecular analysis technologies have resulted in greatly improved CTC enumeration and detection. In this article, we review commercially available technologies used to isolate CTCs from peripheral blood, including immunoaffinity and label-free, physical property-based isolation methods. Although enormous technological progress has been made, especially within the last decade, only a few CTC detection methods have been approved for routine clinical use. Here, we provide an overview of the current CTC isolation methods and examples of their potential application for early diagnosis, prognosis, treatment monitoring, and prediction of resistance to cancer therapy. Furthermore, the challenges that remain to be addressed before such tools are implemented for routine use in clinical settings are discussed.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.1929-1934
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• 2015

Purpose: To determine the diagnostic yield of primary circulating tumor cells in women with suspicion of breast cancer, detected as a result of an abnormal mammography. Materials and Methods: Consecutive women presenting for breast biopsy as a result of a mammogram BiRADs of 3 or more, had an 8ml blood sample taken for primary circulating tumor cell (CTC) detection. Mononuclear cells were obtained using differential gel centrifugation and CTCs identified using standard immunocytochemistry using anti-mammoglobin. A test was determined to be positive if 1 CTC was detected. Results: A total of 144 women with a mean age of $54.7{\pm}15.6$ years participated, 78/144 (53.0%) had breast cancer on biopsy, 65/140 (46.3%) benign pathologies and 1(0.7%) non-Hogkins lymphoma. Increasing BiRADs scores were associated with increased cancer detection (p=0.004, RR 1.00, 4.24, 8.50). CTC mammoglobin positive had a sensitivity of 81.1% and specificity of 90.9%, with positive and negative predictive values of 90.9% and 81.1% respectively. Mammoglobin positive CTCs detected 87% of invasive cancers, while poorly differentiated cancers were negative for mammoglobin. Only 50% of in situ cancers and none of the intraductal cancers had CTCs detected. Menopausal status did not affect the diagnostic yield of the CTC test, which was higher in women with BiRADS 4 mammograms. There was a significant trend (p<0.0001 Chi squared for trends) in CTC detection frequency from intraductal, in situ and invasive (OR 1.00, 8.00, 472.00). Conclusions: The use of primary CTC detection in women suspected of breast cancer has potential uses, especially with invasive cancer, but it failed to detect intra-ductal cancer and 50% of in situ cancer. There was no difference in the diagnostic yield between pre and post menopausal women. To confirm its use in reducing biopsies in women with BIRADs 4a mammagrams and in the detection of interval invasive breast cancer, larger studies are needed.

• Journal of Chest Surgery
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• v.54 no.6
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• pp.460-465
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• 2021

Background: Metastasis and recurrence of primary cancer are the main causes of cancer mortality. Disseminated tumor cells refer to cancer cells that cause metastasis from primary cancer to other organs. Several recent studies have suggested that circulating tumor cells (CTCs) are associated with the clinical stage, cancer recurrence, cancer metastasis, and prognosis. There are several methods of isolating CTCs from whole blood; in particular, using a membrane filtration system is advantageous due to its cost-effectiveness and availability in clinical settings. In this study, an animal model of lung cancer was established in nude mice using the human large cell lung cancer cell line H460. Methods: Six-week-old nude mice were used. The H460 lung cancer cell line was injected subcutaneously into the nude mice. Blood samples were obtained from the orbital area before cell line injection, 2 weeks after injection, and 2 weeks after tumor excision. Blood samples were filtered using a polycarbonate 12-well Transwell membrane (Corning Inc., Corning, NY, USA). An indirect immunofluorescence assay was performed with the epithelial cell adhesion molecule antibody. The number of stained cells was counted using fluorescence microscopy. Results: The average size of the tumor masses was 35.83 mm. The stained cells were counted before inoculation, 2 weeks after inoculation, and 2 weeks after tumor excision. Cancer cells generally increased after inoculation and decreased after tumor resection. Conclusion: The CTC detection method using the commercial polycarbonate 12-well Transwell (Corning Inc.) membrane is advantageous in terms of cost-effectiveness and convenience.

• ETRI Journal
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• v.37 no.2
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• pp.233-240
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• 2015

The novelty of this study resides in a 6"-wafer-level microfabrication protocol for a microdevice with a fluidic control system for the separation of circulating tumor cells (CTCs) from human whole blood cells. The microdevice utilizes a lateral magnetophoresis method based on immunomagnetic nanobeads with anti-epithelial cell adhesive molecule antibodies that selectively bind to epithelial cancer cells. The device consists of a top polydimethylsiloxane substrate for microfluidic control and a bottom substrate for lateral magnetophoretic force generation with embedded v-shaped soft magnetic microwires. The microdevice can isolate about 93% of the spiked cancer cells (MCF-7, a breast cancer cell line) at a flow rate of 40/100 mL/min with respect to a whole human blood/buffer solution. For all isolation, it takes only 10 min to process 400 mL of whole human blood. The fabrication method is sufficiently simple and easy, allowing the microdevice to be a mass-producible clinical tool for cancer diagnosis, prognosis, and personalized medicine.