• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4555-4561
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• 2014

Background: Silencing due to methylation of suppressor of cytokine signaling-3 (SOCS-3), a negative regulator gene for the JAK/STAT signaling pathway has been reported to play important roles in leukemogenesis. Imatinib mesylate is a tyrosine kinase inhibitor that specifically targets the BCR-ABL protein and induces hematological remission in patients with chronic myeloid leukemia (CML). Unfortunately, the majority of CML patients treated with imatinib develop resistance under prolonged therapy. We here investigated the methylation profile of SOCS-3 gene and its downstream effects in a BCR-ABL positive CML cells resistant to imatinib. Materials and Methods: BCR-ABL positive CML cells resistant to imatinib (K562-R) were developed by overexposure of K562 cell lines to the drug. Cytotoxicity was determined by MTS assays and $IC_{50}$ values calculated. Apoptosis assays were performed using annexin V-FITC binding assays and analyzed by flow cytometry. Methylation profiles were investigated using methylation specific PCR and sequencing analysis of SOCS-1 and SOCS-3 genes. Gene expression was assessed by quantitative real-time PCR, and protein expression and phosphorylation of STAT1, 2 and 3 were examined by Western blotting. Results: The $IC_{50}$ for imatinib on K562 was 362nM compared to 3,952nM for K562-R (p=0.001). Percentage of apoptotic cells in K562 increased upto 50% by increasing the concentration of imatinib, in contrast to only 20% in K562-R (p<0.001). A change from non-methylation of the SOCS-3 gene in K562 to complete methylation in K562-R was observed. Gene expression revealed down-regulation of both SOCS-1 and SOCS-3 genes in resistant cells. STAT3 was phosphorylated in K562-R but not K562. Conclusions: Development of cells resistant to imatinib is feasible by overexposure of the drug to the cells. Activation of STAT3 protein leads to uncontrolled cell proliferation in imatinib resistant BCR-ABL due to DNA methylation of the SOCS-3 gene. Thus SOCS-3 provides a suitable candidate for mechanisms underlying the development of imatinib resistant in CML patients.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.98-114
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• 2002

The completion of the draft sequence of the human genome has provided us with a partial list of known and putative human genes, the total number of which is estimated between 30, 000 and 45, 000 (1, 2). These genes provide many potential targets for drugs, some of which may be useful in stopping the growth of cancers. The development of gene-targeting anticancer drugs could be greatly facilitated by the ability to narrow down the list of human genes to those that are necessary for the growth of tumor cells. (omitted)

• 대한위암학회:학술대회논문집
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• 2003.04a
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• pp.20-20
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• 2003

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.405-406
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• 2003

DNA is known as the genetic material in cells. Various environmental factors can cause DNA damages. One of them is sunlight. The life on earth depends on the sunlight, but on the other hand, the UV light in sunlight can cause skin DNA damages. When these damages are not fully repaired before replication, they can lead to mutations of oncogenes and tumour suppressor gene and result in photo carcinogenesis, in the end, skin cancer.(omitted)

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.281.2-281
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• 1999

No Abstract, See Full Text

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.518-524
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• 2008

Chromosome 18q alteration plays a key role in colorectal tumorigenesis, and loss of heterozygosity at 18q is associated with a poor prognosis in colon cancer. DCC(Deleted in Colorectal Cancer) is a putative tumor- suppressor gene at 18q21 that encodes a transmembrane protein with structural similarity to neural cell adhesion molecule that is involved in both epithelial and neuronal cell differentiation. DCC is implicated in regulation of cell growth, survival and proliferation. Thus, tumor progression in squamous cell carcinoma, stomach cancer, colorectal cancer correlates with downregulation of DCC expression. The mechanism for DCC suppression is associated with hypermethylation of the DCC gene promoter region. Hence, the goal of this study is to identify the promoter methylation responsible for the down-regulation of DCC expression in oral squamous cell carcinoma. 12 of tissue specimens for the study are excised and gathered from 12 patients who are diagnosed as SCC in department of OMS, dental hospital, dankook university. To find expression of DCC in each tissue samples, immunohistochemical staining, RT-PCR gene analysis and methylation specific PCR are processed. The results are as follows. 1. In the DCC gene RT-PCR analysis, 5(41.6%) of 12 specimens of oral squamous cell carcinoma did not expressed DCC gene. 2. In the promoter methylation specific PCR analysis, 5(41.6%) of 12 specimens showed promoter methylation of DCC gene. 3. In the immunohistochemical staining of poor differentiated and invasive oral squamous cell carcinoma, loss of DCC expression was observed. These findings suggest that methylation of the DCC gene may play a role in loss of gene expression in invasive oral squamous cell carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4689-4693
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• 2012

Lung cancer is the most common type of cancer and one of the leading causes of death in the world. Genetic factors play an important role in its development. PDCD6, the encoding gene for programmed cell death protein 6, may function as a tumor suppressor gene. Non-small cell lung cancer (NSCLC) contributes about 80% to newly histologically diagnosed lung cancer patients. To explore the relationship between PDCD6 and NSCLC, we examined two single nucleotide polymorphisms(rs3756712 G/T andrs4957014 G/T, both in the intron region) of the PDCD6gene.A hospital-based case-control study was carried out including 302 unrelated NSCLC patients and 306 healthy unrelated subjects. Significantly increased NSCLC risk was found to be associated with the T allele of rs4957014 (P=0.027, OR=0.760, 95%CI=0.596-0.970). The genotype and allele frequencies of rs3756712 did not shown any significant difference between NSCLC group and controls (P=0.327, OR=0.879, 95%CI=0.679-1.137). In conclusion, we firstly demonstrated the association between the PDCD6 gene and risk of NSCLC in a Chinese Han population.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9607-9610
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• 2014

Breast cancer, a leading cause of death among women in most countries worldwide, is rapidly increasing in incidence in Vietnam. One of biomarkers is the disruption of the genetic material including epigenetic changes like DNA methylation. With the aim of finding hypermethylation at CpG islands of promoter of BRCA1 gene, belonged to the tumor suppressor gene family, as the biomarker for breast cancer in Vietnamese population, sensitive methyl specific PCR (MSP) was carried out on 115 samples including 95 breast cancer specimens and 20 normal breast tissues with other diseases which were obtained from Ho Chi Minh City Medical Hospital, Vietnam. The result indicated that the frequency of BRCA1 hypermethylation reached 82.1% in the cases (p<0.001). In addition, the DNA hypermethylation of this candidate gene increased the possibility to be breast cancer with high incidence via calculated odd ratios (p<0.05). In conclusion, hypermethylation of this candidate gene could be used as the promising biomarker application with Vietnamese breast cancer patients.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.1235-1239
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• 2015

Background: Fragile histidine triad (FHIT) gene is a tumor suppressor gene which involved in breast cancer pathogenesis. Epigenetics alterations in FHIT contributes to tumorigenesis of breast cancer. Objective: Our objective was to study FHIT promoter region hypermethylation in Egyptian breast cancer patients and its association with clinicopathological features. Materials and Methods: Methylation-specific polymerase chain reaction was performed to study the hypermethylation of FHIT promoter region in 20 benign breast tissues and 30 breast cancer tissues. Results: The frequency of hypermethylation of FHIT promoter region was significantly increased in breast cancer patients compared to bengin breast disease patients. The Odd's ratio (95%CI) of development of breast cancer in individuals with FHIT promoter hypermethylation (MM) was 11.0 (1.22-250.8). There were also significant associations between FHIT promoter hypermethylation and estrogen, progesterone receptors negativity, tumor stage and nodal involvment in breast cancer pateints. Conclusions: Our results support an association between FHIT promotor hypermethylation and development of breast cancer in Egyptian breast cancer patients. FHIT promoter hypermethylation is associated with some poor prognostic features of breast cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2383-2388
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• 2016

Background: The reversion-inducing-cysteine-rich protein with Kazal motifs (RECK) gene is a novel transformation suppressor gene linked to several malignancies. Objective: To analyze any association between RECK gene rs10814325 single-nucleotide polymorphism (SNP) and HCC susceptibility with various clinicopathological and laboratory data. Materials and Methods: RECK gene rs10814325 SNP was estimated, using real-time PCR, in 30 HCC patients on top of HCV infection, 30 HCV related cirrhotic patients and 30 healthy controls. Results: No special pattern of association could be detected on comparing the RECK gene rs10814325 genotypes(P=0.5), or alleles(P=0.49) among the studied groups. HCC patients with TT genotype had younger age (mean of $54.1{\pm}6.0$ years vs $60.6{\pm}10.2$ years for TC/CC genotypes, P=0.035). Abdominal distension was significantly greater in TT genotype patients (75% vs 30%for TC/CC genotypes, P=0.045). The TT genotype was present in 75% of patients with lymph node metastasis. Serum GGT levels were higher in TT genotype patients [80 (48.5-134.8) IU/L vs 40 (33-87.5) IU/L for TC/CCgenotypes], and lower limb edema was observed in 60% for TT vs 20% for TC/CCgenotypes, but both just failed to reach significance (p=0.05 and p=0.06 respectively). Conclusions: RECK gene rs10814325 T>C could not be considered a risk factor for HCC development on top of HCV, but may be related to the disease progression and metastasis.