• Biomedical Science Letters
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• v.10 no.4
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• pp.507-514
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• 2004

The Pseudomonas aeruginosa isolated from the clinical specimens has a mutation on the QRDR (quinolone resistance determining region). There were obvious mutations in both gyrA and parC gene which are major targets of quinolone. Simultaneous mutations were found two sites or more on these genes in all of ten strains. GyrB or parE gene had only silent mutation without converted amino acids. We confirmed that P. aeruginosa from clinical specimens exhibited decreased sensitivity to fluroquiolone due to changed Thr-83→lle and Asp-87→Asn types on gyrA and altered Ser-87→Leu type on parC. This is the first finding that a new Met-93→Thr type on parC as well as mutations on gyrB or parE genes differed from existing patterns. This study showed more mutations of gyrA rather than parC, suggesting that change of Type Ⅳ topoisomerase is more serious than that of type Ⅱ (DNA gyrase).

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4509-4513
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• 2013

Chronic hepatitis B virus (HBV) infection has long been the most common cause of hepatocellular carcinoma (HCC). However, some aspects of the pathogenesis of HBV infection and genesis of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) are still inconclusive. An increasing number of published studies indicate that hepatitis B virus mutations are associated with risk of HCC. These variations include, in particular, mutations in ORF S,C,X gene regions. This mini-review summarizes results of clinical studies and molecular mechanisms on the possible relations of HBV mutations with the development of hepatocellular carcinoma.

• Journal of Microbiology
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• v.41 no.2
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• pp.115-120
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• 2003

Mex67p/Tap are evolutionally conserved mRNA export factors. To identify mutations in genes that are functionally linked to mex67 with respect to mRNA export, we used a synthetic lethal genetic screen in Schizosaccharomyces pombe. Three synthetic lethal mutants were isolated and mutations in these mutants defined separate complementation groups. These mutants exhibited the accumulation of poly A$\^$+/ RNA in the nucleus, with a decrease in the cytoplasm under synthetically lethal conditions, suggesting that the mutations cause an mRNA nuclear export defect. In addition, the S. pombe genes that were found to be involved in mRNA export did not suppress the synthetic lethality of these mutants. These results indicate that the isolated mutants contain mutations in new genes, which are involved in mRNA export from the nucleus.

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.101-106
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• 2016

The epidermal growth factor receptor(EGFR) protein kinase signaling is an important pathway in cancer development and recently reported that EGFR and its kinase domain molecules are mutated in various of cancers including head and neck cancer. Functional deregulation of EGFR due to mutations in coding exons and copy number amplification is the most common event in cancers, especially among receptor tyrosine kinases(TK). We have analyzed Korean oral squamous cell carcinomas (OSCC) cell lines for mutations in EGFRTK. Exons encoding the hot-spot regions in the TK domain of EGFR (exons 17 to 23) were amplified by using polymerase chain reaction(PCR) and sequenced directly. EGFR expression was also analyzed in 8 OSCC cell lines using western blotting. Data analysis of the EGFR exons 17 to 23 coding sequences did not show any mutations in the 8 OSCC cell lines that were analyzed. The absence of mutations indicate that protein overexpression might be responsible for activation rather than mutation.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3525-3529
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• 2010

Tyrosine kinase inhibitors (TKIs) are currently used in the treatment of patients with advanced lung cancer. Recent studies on non-small cell lung cancer have shown that some patients carry somatic mutations in the epidermal growth factor receptor (EGFR) gene. Such mutations correlate with the effectiveness of certain TKIs. To detect a small amount of mutant EGFR among an abundance of wild-type EGFR, we have developed a highly sensitive and simple method using PNA-mediated real-time PCR clamping. The PNA-mediated real-time PCR clamping enables detection of EGFR mutants down to approximately 1% mutant -to- wild type. The total assay time was short as it required only 2.0 hr. Thus, PNA-mediated real-time PCR clamping can easily be applied to clinical samples for identification of DNA carrying EGFR mutations and also appear to be the best assay to detect somatic mutations.

• Journal of Genetic Medicine
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• v.7 no.1
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• pp.1-8
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• 2010

Hemophilia A is a sex-linked recessive coagulation disorder associated with diverse mutations of the factor VIII gene and a variety of phenotypes. The type of mutation involved dictates the activity of factor VIII, and in turn the severity of bleeding episodes and development of alloantibodies against factor VIII (inhibitors). Missense mutations are the most common genetic risk factors for hemophilia A, especially mild to moderate cases, but carry the lowest risk for inhibitor development. On the other hand, intron 22 inversion is the most common mutation associated with severe hemophilia A and is associated with high risk of inhibitor formation. Large deletions and nonsense mutations are also associated with high risk of inhibitor development. Additional mutations associated with hemophilia A include frameshift and splice site mutations. It is therefore valuable to assess the mutational backgrounds of hemophilia A patients in order to to interpret their symptoms and manage their health problems.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.6
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• pp.525-530
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• 2013

Multidrug resistance 3 (MDR3) is expressed on the canalicular membrane of the hepatocytes and plays an important role in protecting the liver from bile acids. Altered ABCB4 gene expression can lead to a rare hepatic disease, low phospholipid-associated cholelithiasis (LPAC). In this study, we characterized 3 ABCB4 mutations in LPAC patients using various in vitro assay systems. We first measured the ability of each mutant to transport paclitaxel and then the mechanisms by which these mutations might change MDR3 transport activity were determined using immunoblotting, cell surface protein biotinylation, and immunofluorescence. Through a membrane vesicular transport assay, we observed that the uptake of paclitaxel was significantly reduced in membrane vesicles expressing 2 ABCB4 mutations, F165I and S320F. Both mutants showed significantly decreased total and cell surface MDR3 expression. These data suggest two missense mutations of ABCB4 may alter function of MDR3 and ultimately can be determined as LPAC-causing mutations.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5871-5874
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• 2012

Around 1.35 million people of worldwide suffer from breast cancer each year, whereas in India, 1 in every 17 women develops the disease. Mutations of the Breast Cancer 1 (BRCA1) gene account for the majority of breast/ovarian cancer families. The purpose of study was to provide a prevalence of BRCA1 germline mutations in the North-East Indian population. In relation to the personal and family history with the breast cancer, we found mutations in 6.25% and 12.5% respectively. Three mutations, 185DelAG, 1014DelGT and 3889DelAG, were observed in our North-East Indian patients in exons 2 and 11, resulting in truncation of the BRCA1 protein by forming stop codons individually at amino acid positions 39, 303 and 1265. Our results point to a necessity for an extensive mutation screening study of high risk breast cancer cases in our North-East Indian population, which will provide better decisive medical and surgical preventive options.

• BMB Reports
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• v.43 no.10
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• pp.693-697
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• 2010

Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant syndrome characterized by predisposition to early-onset cancers. HNPCC is caused by heterozygous loss-of-function mutations within the mismatch repair genes MLH1, MSH2, MSH6, PMS1, and PMS2. We genotyped the MLH1 and MSH2 genes in patients suffering from Lynch syndrome and in 11 unrelated patients who were diagnosed with colorectal cancer and had subsequently undergone surgery. Five Lynch syndrome patients carried germline mutations in MLH1 or MSH2. Two of these were identified as known mutations in MLH1: deletion of exon 10 and a point mutation (V384D). The remaining three patients exhibited novel mutations: a duplication (937_942dupGAAGTT) in MLH1; deletion of exons 8, 9, and 10; and a point mutation in MLH1 (F396I) combined with multiple missense mutations in MSH2 (D295G, K808E, Q855P, and I884T). The findings underline the importance of efficient pre-screening of conspicuous cases.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5019-5022
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• 2014

Recently, mutations in the genes involved in cell cycle control, including CHEK2, are being considered as etiological factors in different kinds of cancers. The CHEK2 protein plays an important role in protecting damaged DNA from entering mitosis. In this study the potential effects of two common mutations $IVS2+1G{\rightarrow}A$ and Ile157Thr of CHEK2 gene in differentiated thyroid carcinoma (DTC) were evaluated. A total of 100 patients admitted to the Research Institute for Nuclear Medicine were diagnosed with DTC based on pathology reports of surgery samples. An additional 100 people were selected as a control group with no cancer history. PCR-HRM (high resolution melting) analysis was performed to deal with each of mutations in all case and control samples separately. During the analysis of $IVS2+1G{\rightarrow}A$ and Ile157Thr mutations of CHEK2 gene in the case and control groups, all the samples were identified as wild homozygote type. The finding suggests that $IVS2+1G{\rightarrow}A$ and Ile157Thr mutations of CHEK2 gene do not constitute a risk factor for DTC in the Iranian population. However, further studies with larger population are required to confirm the outcome.