Epigenetics: an emerging player in gastric cancer.

Kang, Changwon,Song, Ji-Joon,Lee, Jaeok,Kim, Mi Young WJG Press 2014 WORLD JOURNAL OF GASTROENTEROLOGY Vol.20 No.21

<P>Cancers, like other diseases, arise from gene mutations and/or altered gene expression, which eventually cause dysregulation of numerous proteins and noncoding RNAs. Changes in gene expression, i.e., upregulation of oncogenes and/or downregulation of tumor suppressor genes, can be generated not only by genetic and environmental factors but also by epigenetic factors, which are inheritable but nongenetic modifications of cellular chromosome components. Identification of the factors that contribute to individual cancers is a prerequisite to a full understanding of cancer mechanisms and the development of customized cancer therapies. The search for genetic and environmental factors has a long history in cancer research, but epigenetic factors only recently began to be associated with cancer formation, progression, and metastasis. Epigenetic alterations of chromatin include DNA methylation and histone modifications, which can affect gene-expression profiles. Recent studies have revealed diverse mechanisms by which chromatin modifiers, including writers, erasers and readers of the aforementioned modifications, contribute to the formation and progression of cancer. Furthermore, functional RNAs, such as microRNAs and long noncoding RNAs, have also been identified as key players in these processes. This review highlights recent findings concerning the epigenetic alterations associated with cancers, especially gastric cancer.</P>

Behçet’s disease risk association fine-mapped on the <i>IL23R</i> – <i>IL12RB2</i> intergenic region in Koreans

Kang, Eun Ha,Kim, Sewon,Park, Min Young,Choi, Ji Yong,Choi, In Ah,Kim, Min Jung,Ha, You-Jung,Lee, Eun Young,Lee, Yun Jong,Lee, Eun Bong,Kang, Changwon,Song, Yeong Wook BioMed Central 2017 ARTHRITIS RESEARCH AND THERAPY Vol.19 No.-

<P><B>Background</B></P><P>Behçet’s disease (BD) susceptibility had been associated with single-nucleotide polymorphisms (SNPs) in <I>IL23R</I>–<I>IL12RB2</I>, <I>IL10, STAT4,</I> or <I>ERAP1</I> locus in Japanese, Turkish, Chinese, and other populations, but not in a Korean genome-wide association study (GWAS). We aimed to fine-map BD risk association of these four loci using extensive imputation and additional genotyping for replication.</P><P><B>Methods</B></P><P>In the discovery phase, 369 patients with BD enrolled in the previous Korean GWAS and 2000 controls retrieved from a population-based cohort of healthy Koreans were imputed for their genotypes of all SNPs in the four loci using the Asian data of the 1000 Genomes Project as reference. For genotype imputation of <I>ERAP1</I> SNPs, the adjacent <I>ERAP2</I> SNPs were also covered. For the 10 most significantly associated SNPs (8 imputed and 2 GWAS-genotyped), an additional 84 patients with BD and 283 healthy controls were genotyped for replication. The results from the discovery and replication phases were pooled for meta-analysis using the Mantel-Haenszel test to estimate the odds ratio (OR) and 95% confidence interval (CI).</P><P><B>Results</B></P><P>An <I>IL23R</I>–<I>IL12RB2</I> intergenic SNP rs1495965 was significantly associated with BD risk (OR (95% CI) = 1.5 (1.3, 1.7), <I>P</I> = 2.5 × 10<SUP>−7</SUP>) in the pooled meta-analysis of the discovery (1.4 (1.2, 1.7), <I>P</I> = 4.9 × 10<SUP>−7</SUP>) and replication (1.9 (1.3, 2.6), <I>P</I> = 6.0 × 10<SUP>−4</SUP>) phases. BD risk association was fine-mapped on the intergenic region rather than the two flanking genes, as rs1495966 and rs4655535, almost perfectly correlated with rs1495965 (<I>r</I><SUP>2</SUP> = 0.99), were also located in the same intergenic region. Consistent with previous reports, the <I>P</I> values tended to be lower within <I>IL23R</I> than <I>IL12RB2</I>. On the other hand, several <I>IL10</I> SNPs were suggested for association in the discovery phase but all failed in the replication phase. No SNP in <I>ERAP1</I>–<I>ERAP2</I> and <I>STAT4</I> was suggested even in the discovery phase.</P><P><B>Conclusions</B></P><P>BD susceptibility association was fine-mapped on the intergenic region between <I>IL23R</I> and <I>IL12RB2</I> as marked by three correlated SNPs, rs1495965, rs1495966, and rs4655535.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1186/s13075-017-1435-5) contains supplementary material, which is available to authorized users.</P>

A functional haplotype of the PADI4 gene associated with increased rheumatoid arthritis susceptibility in Koreans

Kang, Changsoo Paul,Lee, Hye-Soon,Ju, Hyoungseok,Cho, Hyunmi,Kang, Changwon,Bae, Sang-Cheol Wiley Subscription Services, Inc., A Wiley Company 2006 Vol.54 No.1

<B>Objective</B><P>Anticitrullinating autoantibodies are specific markers for rheumatoid arthritis (RA). A functional haplotype of 4 exonic single-nucleotide polymorphisms (SNPs) in a citrullinating enzyme, peptidylarginine deiminase 4 (PADI4), was shown to be associated with susceptibility to RA in a Japanese population and was shown to increase the stability of PADI4 messenger RNA. However, the association was not confirmed in 4 subsequent studies involving Caucasian RA patients living in the UK, a French Caucasian population, and a Spanish population. The aim of the current study was to investigate the association of SNPs in the PADI4 gene with RA in a Korean population.</P><B>Methods</B><P>Four exonic SNPs of the PADI4 gene (padi4_89, padi4_90, padi4_92, and padi4_104) were genotyped in 545 unrelated patients with RA and 392 controls, using the MassArray SNP genotyping system. Allelic, genotypic, and haplotypic associations of the SNPs with RA susceptibility were examined using the chi-square test and multivariate logistic regression analyses.</P><B>Results</B><P>Increased RA susceptibility was significantly associated with the minor alleles of padi4_89 (P = 2.3 × 10<SUP>−5</SUP>), padi4_90 (P = 2.3 × 10<SUP>−5</SUP>), padi4_92 (P = 2.1 × 10<SUP>−5</SUP>), and padi4_104 (P = 1.1 × 10<SUP>−3</SUP>) and the haplotype carrying the 4 minor alleles (P = 1.0 × 10<SUP>−4</SUP>). Genotypes carrying the minor alleles and HLA–DRB1 shared epitope (SE) alleles (P = 9.4 × 10<SUP>−21</SUP>) were also associated with increased RA susceptibility. The genotypic associations were sustained among individuals who did not carry any SE alleles, except in the case of padi4_104. Individuals carrying the risk SNPs and/or SE alleles were more susceptible to RA than were individuals carrying neither risk SNPs nor SE alleles.</P><B>Conclusion</B><P>The PADI4 SNPs and haplotypes are associated with RA susceptibility in Koreans. Thus, the association of PADI4 with RA may depend on genetic heterogeneity between Asians and Europeans.</P>

Recent advances in mass spectrometry-based proteomics of gastric cancer

Kang, Changwon,Lee, Yejin,Lee, J Eugene Baishideng Publishing Group Inc 2016 World journal of gastroenterology Vol.22 No.37

<P>The last decade has witnessed remarkable technological advances in mass spectrometry-based proteomics. The development of proteomics techniques has enabled the reliable analysis of complex proteomes, leading to the identification and quantification of thousands of proteins in gastric cancer cells, tissues, and sera. This quantitative information has been used to profile the anomalies in gastric cancer and provide insights into the pathogenic mechanism of the disease. In this review, we mainly focus on the advances in mass spectrometry and quantitative proteomics that were achieved in the last five years and how these up-and-coming technologies are employed to track biochemical changes in gastric cancer cells. We conclude by presenting a perspective on quantitative proteomics and its future applications in the clinic and translational gastric cancer research.</P>

불확실성기반 의미적 정보 강화를 통한 3차원 점유 그리드 예측 네트워크 성능 개선

강창원(Changwon Kang),김예철(Yecheol Kim),최준원(Jun Won Choi) 한국통신학회 2024 한국통신학회 학술대회논문집 Vol.2024 No.1

한글 문서인식 시스템에 관한 연구

강현철,이병래,김창원,이완주,최지선,이한욱,박규태 연세대학교 산업기술연구소 1988 논문집 Vol.20 No.2

This paper describes the computer vision system which recognizes characters in Korean documents. The system consists of the input, character extraction, preprocessing and recognition unit. Characters in documents are extracted from character strings which are extracted from input document in row major. In preprocessing, skeleton of the extracted character is obtained using image thinning technique. Recognition of a character is performed by the isometric array parser which permits the alteration of pattern and avoids the unnecessary noise occuring in conversion of patterns into 1-D primitive strings. The result shows that the recognition rate is about 91.6% wherease the errorneous recognition rate is about 6.3% on handwritten Korean characters. In comparison with the conventional approach the syntactic approach using array paper is able to reduce the recognition time and to obtain the higher recognition rate.

Online Unstructured Data Analysis Models with KoBERT and Word2vec: A Study on Sentiment Analysis of Public Opinion in Korean

Changwon Baek,Jiho Kang,SangSoo Choi 한국지능시스템학회 2023 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.23 No.3

Online news articles and comments play a vital role in shaping public opinion. Numerous studies have conducted online opinion analyses using these as raw data. Bidirectional encoder representations from transformer (BERT)-based sentiment analysis of public opinion have recently attracted significant attention. However, owing to its limited linguistic versatility and low accuracy in domains with insufficient learning data, the application of BERT to Korean is challenging. Conventional public opinion analysis focuses on term frequency; hence, low-frequency words are likely to be excluded because their importance is underestimated. This study aimed to address these issues and facilitate the analysis of public opinion regarding Korean news articles and comments. We propose a method for analyzing public opinion using word2vec to increase the word-frequency-centered analytical limit in conjunction withKoBERT, which is optimized for Korean language by improving BERT. Naver news articles and comments were analyzed using a sentiment classification model developed on the KoBERT framework. The experiment demonstrated a sentiment classification accuracy of over 90%. Thus, it yields faster and more precise results than conventional methods. Words with a low frequency of occurrence, but high relevance, can be identified using word2vec.

스프링 강성이 토크컨버터 댐퍼 스프링의 동적 히스테리시스에 미치는 영향에 관한 연구

손창원(Changwon Son),강철웅(Cheolwung Kang),장재덕(Jaeduk Jang),주인식(Insik Joo) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

The Lock-up clutch of a torque converter directly transmits the engine power to the transmission in order to achieve a more fuel economy. Damper spring, a core part of lock-up system, makes the powertrain system stabilized by reducing the fluctuation torque of any engine system when lock-up clutch is operated. In addition, this part helps the improvement of total vehicle systems by increasing spring characteristics in aspects of the design facilities. This paper is to be used to determine basic materials for the damper system spring to study the main factors by comparative analysis of hysteresis of two different spring stiffness of damper system.

코퍼스 기반 중학교 영어 교과서 be 동사 부정 축약 분석

강혜선 ( Kang Hye-sun ),김민경 ( Kim Minkyung ),신창원 ( Shin Changwon ) 글로벌영어교육학회(구 호남영어교육학회) 2019 Studies in English education Vol.24 No.1

When be-verb negation is contracted, either verb contraction or negative contraction can be selected, based on the types of preceding subjects. Thus, a pronoun subject tends to be with verb contraction more frequently (e.g. She’s not/They’re not), while a full noun subject is more likely to occur with negative contraction (e.g. The classroom isn’t). In this regard, the current study aims to investigate if middle school English textbooks provide sufficient examples of English native speakers’ preference in using be-verb negative contraction. To this end, a small corpus was compiled, comprising all the listening materials from 14 middle school English textbooks. From this corpus, all the sentences including verb contraction and negative contraction each were extracted using a concordancer program to see what type of subject each contraction form occurs with more frequently. The results of this analysis showed that when the subject is a pronoun, verb contraction is favored over negative contraction, whereas negative contraction is more likely to be with a full noun phrase, suggesting that the English textbook present language input similar to English native speakers’ preference in using be-verb negative contraction.

사이버 방어 훈련 목적의 자동화된 대항군 모의를 위한 네트워크 분해 및 Attack Tree 연산 기술 활용 방안

강홍구(Honggoo Kang),김동화(Donghwa Kim),이창원(Changwon Lee),안명길(Myung Kil Ahn) 한국정보과학회 2019 한국정보과학회 학술발표논문집 Vol.2019 No.6