• Title/Summary/Keyword: cancer genomics

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Functional roles of CTCF in breast cancer

  • Oh, Sumin;Oh, Chaeun;Yoo, Kyung Hyun
    • BMB Reports
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    • v.50 no.9
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    • pp.445-453
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    • 2017
  • CTCF, Zinc-finger protein, has been identified as a multifunctional transcription factor that regulates gene expression through various mechanisms, including recruitment of other co-activators and binding to promoter regions of target genes. Furthermore, it has been proposed to be an insulator protein that contributes to the establishment of functional three-dimensional chromatin structures. It can disrupt transcription through blocking the connection between an enhancer and a promoter. Previous studies revealed that the onset of various diseases, including breast cancer, could be attributed to the aberrant expression of CTCF itself or one or more of its target genes. In this review, we will describe molecular dysfunction involving CTCF that induces tumorigenesis and summarize the functional roles of CTCF in breast cancer.

Prostate Stem Cell Antigen Single Nucleotide Polymorphisms Influence Risk of Estrogen Receptor Negative Breast Cancer in Korean Females

  • Kim, Sook-Young;Yoo, Jae-Young;Shin, Ae-Sun;Kim, Yeon-Ju;Lee, Eun-Sook;Lee, Yeon-Su
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.1
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    • pp.41-48
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    • 2012
  • Introduction: Breast cancer is the second leading cancer in Korean women. To assess potential genetic associations between the prostate stem cell antigen (PSCA) gene in the chromosome 8q24 locus and breast cancer risk in Korean women, 13 SNPs were selected and associations with breast cancer risk were analyzed with reference to hormone receptor (HR) and menopausal status. Methods:We analyzed DNA extracted from buffy coat from 456 patients and 461 control samples, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) based upon region-specific PCR followed by allelespecific single base primer extension reactions. Risks associated with PSCA genotypes and haplotypes were estimated with chi-square test (${\chi}^2$-test), and polytomous logistic regression models using odds ratios (OR) and 95% confidence intervals (CIs), by HR and menopausal status. Results: In case-control analysis, odds ratios (OR) of rs2294009, rs2294008, rs2978981, rs2920298, rs2976395, and rs2976396 were statistically significant only among women with estrogen receptor (ER) negative cancers, and those of rs2294008, rs2978981, rs2294010, rs2920298, rs2976394, rs10216533, and rs2976396 were statistically significant only in pre-menopausal women, and not in postmenopausal women. Risk with the TTGGCAA haplotype was significantly elevated in ER (-) status (OR= 1.48, 95% CI= 1.03~2.12, p<0.05). Especially risk of allele T of rs2294008 is significantly low in pre-menopausal breast cancer patients and AA genotype of rs2976395 in ER (-) status represents the increase of OR value. Conclusion: This report indicated for the first time that associations exist between PSCA SNPs and breast cancer susceptibility in Korean women, particularly those who are pre-menopausal with an estrogen receptor negative tumor status.

cDNA Microarray Analysis of Transcriptional Response to Hyperin in Human Gastric Cancer Cells

  • Jeoung, Dooil;Kim, Jae-Hwan;Lee, Youn-Hyung;Myungin Baek;Lee, Seongeun;Baek, Nam-In;Kim, Hae-Yeong
    • Journal of Microbiology and Biotechnology
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    • v.12 no.4
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    • pp.664-668
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    • 2002
  • Antioxidants either scavenge superoxide and free radicals or stimulate the detoxification mechanisms within cells, resulting in increased detoxification of free radicals formation. Hyperin, isolated from the stem of Uncaria rhynchophylla, prevented oxygen radical formation and inhibited lipid oxidation. The effective concentrations were 31.3 $\mu$M for a radical scavenging assay and 2.2 $\mu$M for a microsome assay. cDNA microarray analysis to determine which genes were modulated by hyperin found that 50 genes were upregulated and 37 genes were downregulated in SNU-668 human gastric cancer cells. Among these genes, thirteen genes that were significantly affected by hyperin were verified by RT-PCR for their effect of genetic reprogramming.

Frequency of K-RAS and N-RAS Gene Mutations in Colorectal Cancers in Southeastern Iran

  • Naseri, Mohsen;Sebzari, Ahmadreza;Haghighi, Fatemeh;Hajipoor, Fatemeh;Razavi, Fariba Emadian
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.9
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    • pp.4511-4515
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    • 2016
  • Background: K-RAS and N-RAS gene mutations cause resistance to treatment in patients with colorectal cancer. Based on this, awareness of mutation of these genes is considered a clinically important step towards better diagnosis and appropriate treatment. Materials and Methods: Fifty paraffin-embedded blocks of colorectal cancer were obtained from Imam Reza Hospital of Birjand, Iran. Following DNA extraction, the samples were analyzed for common mutations of exons 2, 3 and 4 of KRAS and NRAS genes using real time PCR and pyrosequencing. Results: According to this study, the prevalence of mutations was respectively 28% (14 out of 50) and 2% (1 out of 50) in KRAS and NRAS genes. All the mutations were observed in patients >50 years old. Conclusions: Mutations were found in both KRAS and NRAS genes in colorectal cancers in Iranian patients. Determining the frequency of these mutations in each geographical region may be necessary to benefit from targeted cancer therapy.

Exome sequencing in a breast cancer family without BRCA mutation

  • Noh, Jae Myoung;Kim, Jihun;Cho, Dae Yeon;Choi, Doo Ho;Park, Won;Huh, Seung Jae
    • Radiation Oncology Journal
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    • v.33 no.2
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    • pp.149-154
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    • 2015
  • Purpose: We performed exome sequencing in a breast cancer family without BRCA mutations. Materials and Methods: A family that three sisters have a history of breast cancer was selected for analysis. There were no family members with breast cancer in the previous generation. Genetic testing for BRCA mutation was negative, even by the multiplex ligation-dependent probe amplification method. Two sisters with breast cancer were selected as affected members, while the mother of the sisters was a non-affected member. Whole exome sequencing was performed on the HiSeq 2000 platform with paired-end reads of 101 bp in the three members. Results: We identified 19,436, 19,468, and 19,345 single-nucleotide polymorphisms (SNPs) in the coding regions. Among them, 8,759, 8,789, and 8,772 were non-synonymous SNPs, respectively. After filtering out 12,843 synonymous variations and 12,105 known variations with indels found in the dbSNP135 or 1000 Genomes Project database, we selected 73 variations in the samples from the affected sisters that did not occur in the sample from the unaffected mother. Using the Sorting Intolerant From Tolerant (SIFT), PolyPhen-2, and MutationTaster algorithms to predict amino acid substitutions, the XCR1, DLL1, TH, ACCS, SPPL3, CCNF, and SRL genes were risky among all three algorithms, while definite candidate genes could not be conclusively determined. Conclusion: Using exome sequencing, we found 7 variants for a breast cancer family without BRCA mutations. Genetic evidence of disease association should be confirmed by future studies.

New Lung Cancer Panel for High-Throughput Targeted Resequencing

  • Kim, Eun-Hye;Lee, Sunghoon;Park, Jongsun;Lee, Kyusang;Bhak, Jong;Kim, Byung Chul
    • Genomics & Informatics
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    • v.12 no.2
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    • pp.50-57
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    • 2014
  • We present a new next-generation sequencing-based method to identify somatic mutations of lung cancer. It is a comprehensive mutation profiling protocol to detect somatic mutations in 30 genes found frequently in lung adenocarcinoma. The total length of the target regions is 107 kb, and a capture assay was designed to cover 99% of it. This method exhibited about 97% mean coverage at $30{\times}$ sequencing depth and 42% average specificity when sequencing of more than 3.25 Gb was carried out for the normal sample. We discovered 513 variations from targeted exome sequencing of lung cancer cells, which is 3.9-fold higher than in the normal sample. The variations in cancer cells included previously reported somatic mutations in the COSMIC database, such as variations in TP53, KRAS, and STK11 of sample H-23 and in EGFR of sample H-1650, especially with more than $1,000{\times}$ coverage. Among the somatic mutations, up to 91% of single nucleotide polymorphisms from the two cancer samples were validated by DNA microarray-based genotyping. Our results demonstrated the feasibility of high-throughput mutation profiling with lung adenocarcinoma samples, and the profiling method can be used as a robust and effective protocol for somatic variant screening.