| 1. |
- Dimberg, Jan, et al.
(författare)
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Analysis of APC and IGFBP7 promoter gene methylation in Swedish and Vietnamese colorectal cancer patients
- 2013
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Ingår i: Oncology Letters. - : Spandidos Publications. - 1792-1074 .- 1792-1082. ; 5:1, s. 25-30
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Tidskriftsartikel (refereegranskat)abstract
- The tumour suppressor gene adenomatous polyposis coli (APC) is a key component that drives colorectal carcinogenesis. The reported DNA methylation in the promoter of APC varies greatly among studies of colorectal cancer (CRC) in different populations. Insulin-like growth factor binding protein 7 (IGFBP7), also known as IGFBP‑related protein 1 (IGFBP-rP1), is expressed in various tissue types, including the lung, brain, prostate and gastrointestinal tract, and has been suggested to play a tumour suppressor role against colorectal carcinogenesis. Studies have indicated that IGFBP7 is inactivated by DNA methylation in human colon, lung and breast cancer. In the present study, we used the methylation‑specific polymerase chain reaction to study the methylation status of the APC and IGFBP7 gene promoters in cancerous and paired normal tissue to evaluate its impact on clinical factors and association with ethnicity, represented by Swedish and Vietnamese CRC patients. We also investigated the distribution of CpG islands and the CpG dinucleotide density of each CpG island in the regions which were the subject of our investigation. Overall, normal tissue from Swedish patients exhibited a significantly higher frequency of IGFBP7 gene methylation in comparison with that of Vietnamese patients. Moreover, a significantly higher number of cancer tissues from Vietnamese individuals showed higher levels of methylation versus the paired normal tissue compared with that of Swedish patients. When we studied the methylation in cancer compared with the matched normal tissue in individuals, we found that a significantly higher number of Vietnamese patients had a higher degree of IGFBP7 gene methylation in cancer versus matched normal tissue in comparison with Swedish patients. Taken together, our results suggest that the methylation of the APC and IGFBP7 gene promoter region in cancerous tissue, in combination with the predominance of methylation in normal tissue, may serve as a prognostic factor in CRC patients.
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| 2. |
- Dimberg, Jan, et al.
(författare)
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Detection of Cytomegalovirus DNA in Colorectal Tissue from Swedish and Vietnamese Patients with Colorectal Cancer
- 2013
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Ingår i: Anticancer Research. - 0250-7005 .- 1791-7530. ; 33:11, s. 4947-4950
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Tidskriftsartikel (refereegranskat)abstract
- Background: Human cytomegalovirus (HCMV) has been implicated as a factor, which might be associated with colorectal cancer (CRC) progression. Data from studies with HCMV-infected tumour cell lines have highlighted an oncomodulatory potential of HCMV. In the present study, we aimed to evaluate the prevalence of HCMV DNA in CRC tissue compared to matched normal tissue, and its association with clinical factors.Patients and Methods: We used quantitative real-time polymerase chain reaction assay to detect HCMV DNA in 202 cancerous and paired normal tissue from Swedish (n=119) and Vietnamese (n=83) CRC patients.Results: Overall, the HCMV DNA rate was significantly higher in cancerous in relation to paired normal tissue. Furthermore, a significantly higher frequency (39.8%) of HCMV DNA was observed in cancer tissues from the Vietnamese patients compared to the Swedish patients (15.1%). The prevalence of HCMV DNA in CRC tissue of 50% of those with disseminated disease tended to be higher compared to those with localized disease, with a prevalence of 33.3% in Vietnamese patients.Conclusion: Our observations indicate that the prevalence of HCMV DNA differs significantly between cancer and matched normal tissues. Thus, these data support a possible role of CMV in CRC. Moreover, we noted differences between Swedish and Vietnamese patients, indicating a role of ethnicity.
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| 3. |
- Dimberg, Jan, et al.
(författare)
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Novel and Differential Accumulation of Mitochondrial DNA Deletions in Swedish and Vietnamese Patients with Colorectal Cancer
- 2014
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Ingår i: Anticancer Research. - 0250-7005 .- 1791-7530. ; 34:1, s. 147-152
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Tidskriftsartikel (refereegranskat)abstract
- Background: Mitochondrial DNA (mtDNA) has been proposed to be involved in carcinogenesis and aging. The mtDNA 4977 bp deletion is one of the most frequently observed mtDNA mutations in human tissues and may play a role in colorectal cancer (CRC). In the present study, we aimed to evaluate the frequency of mtDNA 4977 bp deletion in CRC tissues and its association with clinical factors. Patients and Methods: We determined the presence of the 4977 bp common deletion in cancer and normal paired tissue samples from 105 Swedish and 88 Vietnamese patients with CRC using polymerase chain reaction (PCR) assays. Results: The mtDNA 4977 bp deletion was shown to be significantly more frequent in normal tissues in comparison with paired cancer tissues in both Swedish and Vietnamese patients. The 4977 bp common deletion was significantly more frequent in cancer tissues of the Vietnamese patients compared to the Swedish patients, and in Vietnamese cancer tissues, the 4977 bp deletion was significantly over represented in those with localized disease compared to those with disseminated disease. Moreover, we detected nine novel mtDNA deletions and found a significantly higher rate of these in CRC tissues in Swedish in comparison to Vietnamese patients. Conclusion: The mtDNA 4977 bp deletion seems to have an impact on the clinical outcome of CRC in Vietnamese patients, that the Swedish patients accumulate more of the detected novel deletions in CRC tissue compared to Vietnamese patients probably indicates divergent mechanisms in colorectal carcinogenesis.
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