| 31. |
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| 32. |
- Ling, Agnes, 1976-, et al.
(författare)
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TAP1 down-regulation elicits immune escape and poor prognosis in colorectal cancer
- 2017
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Ingår i: Oncoimmunology. - 2162-4011 .- 2162-402X. ; 6:11
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Tidskriftsartikel (refereegranskat)abstract
- The anti-tumor immune response has been shown to be of great prognostic importance in colorectal cancer (CRC) and so has the tumors ability for immune evasion. Our aim of this study was to investigate tumor factors that influence immunity. We used a gene expression array to search for potential mechanisms of tumor immune escape. One candidate gene identified was TAP1, involved in antigen presentation by MHC class I. TAP1 protein expression was evaluated by immunohistochemistry in 436 CRC patients of the Colorectal Cancer in Umeå Study cohort. We found a significant association between a downregulated expression of TAP1 and low infiltration of various subtypes of lymphocytes as well as macrophages. A downregulated expression of TAP1 was further found to be independent of molecular characteristics, suggesting TAP1 down-regulation to reach beyond the well described highly immunogenic MSI CRCs. A low expression of TAP1 was also significantly associated with poor prognosis in patients with CRC, a result that stayed significant in tumor front of early stage tumors (stage I-II) through multivariable analyses. Furthermore, we found that TAP1 expression was inversely correlated with methylation at sites in close proximity to the promoter region. In summary, our results show down-regulation of TAP1 to be a general mechanism of tumor immune escape in CRC and a poor prognostic factor in stage I-II CRC patients. We also suggest that methylation of the TAP1 gene may be a putative mechanism for TAP1 downregulation.
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| 33. |
- Lundberg, Ida V, et al.
(författare)
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SOX2 expression is regulated by BRAF and contributes to poor patient prognosis in colorectal cancer
- 2014
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Ingår i: PLOS ONE. - : Public library of science. - 1932-6203. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- Sporadic colorectal cancer (CRC) is a common malignancy and also one of the main causes of cancer deaths worldwide. Aberrant expression of the transcription factor SOX2 has recently been observed in several cancer types, but its role in CRC has not been fully elucidated. Here we studied the expression of SOX2 in 441 CRC patients by immunohistochemistry and related the expression to clinicopathological and molecular variables and patient prognosis. SOX2 was expressed in 11% of the tumors and was significantly associated to BRAF(V600E) mutation, but not to KRAS mutations (codon 12 and 13). SOX2 positivity was correlated to poor patient survival, especially in BRAF(V600E) mutated cases. In vitro studies showed that cells expressing the constitutively active BRAF(V600E) had increased SOX2 expression, a finding not found in cells expressing KRAS(G12V). Furthermore, blocking downstream BRAF signalling using a MEK-inhibitor resulted in a decreased expression of SOX2. Since SOX2 overexpression has been correlated to increased migration and invasion, we investigated the SOX2 expression in human CRC liver metastasis and found that a SOX2 positive primary CRC also had SOX2 expression in corresponding liver metastases. Finally we found that cells overexpressing SOX2 in vitro showed enhanced expression of FGFR1, which has been reported to correlate with liver metastasis in CRC. Our novel findings suggest that SOX2 expression is partly regulated by BRAF signalling, and an increased SOX2 expression may promote CRC metastasis and mediate a poor patient prognosis.
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| 34. |
- Manjer, Jonas, et al.
(författare)
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Vitamins B2 and B6 and genetic polymorphisms related to one-carbon metabolism as risk factors for gastric adenocarcinoma in the European prospective investigation into cancer and nutrition.
- 2010
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 19:1, s. 28-38
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Tidskriftsartikel (refereegranskat)abstract
- B vitamins and polymorphisms in genes coding for enzymes involved in one-carbon metabolism may affect DNA synthesis and methylation and thereby be implicated in carcinogenesis. Previous data on vitamins B2 and B6 and genetic polymorphisms other than those involving MTHFR as risk factors for gastric cancer (GC) are sparse and inconsistent. In this case-control study nested within the European Prospective Investigation into Cancer and Nutrition cohort, cases (n = 235) and controls (n = 601) were matched for study center, age, sex, and time of blood sampling. B2 and B6 species were measured in plasma, and the sum of riboflavin and flavin mononucleotide was used as the main exposure variable for vitamin B2 status, whereas the sum of pyridoxal 5'-phosphate, pyridoxal, and 4-pyridoxic acid was used to define vitamin B6 status. In addition, we determined eight polymorphisms related to one-carbon metabolism. Relative risks for GC risk were calculated with conditional logistic regression, adjusted for Helicobacter pylori infection status and smoking status. Adjusted relative risks per quartile (95% confidence interval, P(trend)) were 0.85 (0.72-1.01, 0.06) for vitamin B2 and 0.78 (0.65-0.93, <0.01) for vitamin B6. Both relations were stronger in individuals with severe chronic atrophic gastritis. The polymorphisms were not associated with GC risk and did not modify the observed vitamin-cancer associations. In summary, results from this large European cohort study showed an inverse association between vitamin B2 and GC risk, which is borderline significant, and a significant inverse association between vitamin B6 and GC risk.
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| 35. |
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| 36. |
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| 37. |
- Nagel, Gabriele, et al.
(författare)
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Socioeconomic positoon and the risk of gastric and overphageal cancer in the European Prospective into Cancer and Nutrition (EPIC-EURGAST)
- 2007
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 1464-3685 .- 0300-5771. ; 36:1, s. 66-76
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To evaluate the association of socioeconomic position with adenocarcinoma of the oesophagus and stomach. Methods The European Prospective Investigation into Cancer and Nutrition (EPIC) cohort comprises about 520000 participants mostly aged 35-70 years. Information on diet and lifestyle was collected at recruitment. After an average follow-up of 6.5 years, 268 cases with adenocarcinoma of the stomach and 56 of the oesophagus were confirmed. We examined the effect of socioeconomic position on cancer risk by means of educational data and a computed Relative Index of Inequality (RII). In a nested case-control study, adjustment for Helicobacter pylori (H. pylori) infection was performed. Results Higher education was significantly associated with a reduced risk of gastric cancer [vs lowest level of education, hazard ratio (HR): 0.64, 95% Confidence intervals (CI): 0.43-0.981. This effect was more pronounced for cancer of the cardia (HR: 0.42, 95% CI: 0.20-0.89) as compared to non-cardia gastric cancer (HR: 0.66, 95% CI: 0.36-1.22). Additionally, the inverse association of educational level and gastric cancer was stronger for cases with intestinal (extreme categories, HR: 0.13, 95% CI: 0.04-0.44) rather than diffuse histological subtype (extreme categories, HR: 0.71 95% CI: 0.37-1.40). In the nested case-control study, inverse but statistically non-significant associations were found after additional adjustment for H. pylori infection [highest vs lowest level of education: Odds ratio (OR) 0.53, 95% CI: 0.24-1.18]. Educational level was non-significantly, inversely associated with carcinoma of the oesophagus. Conclusion A higher socioeconomic position was associated with a reduced risk of gastric adenocarcinoma, which was strongest for cardia cancer or intestinal histological subtype, suggesting different risk profiles according to educational level. These effects appear to be explained only partially by established risk factors.
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| 38. |
- Palmqvist, Richard, et al.
(författare)
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hTERT gene copy number is not associated with hTERT RNA expression or telomerase activity in colorectal cancer
- 2005
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Ingår i: International Journal of Cancer. - Geneve : International union against cancer. - 0020-7136 .- 1097-0215. ; 116:3, s. 395-400
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Tidskriftsartikel (refereegranskat)abstract
- In a majority of malignant human tumors telomerase activity can be detected, suggesting an immortal phenotype. Expression of the reverse transcriptase subunit, hTERT, in the human telomerase complex is required for telomerase activity. The regulation of hTERT, from gene level to a fully functional protein, is still a poorly understood process. Increased copy number of the hTERT gene has been demonstrated in a significant portion of established cell lines and tumors of different origin but its relevance for telomerase activity levels is unclear. In the present study, we examined the hTERT gene copy number using fluorescence in situ hybridization (FISH) in samples from 64 colorectal carcinomas and an increased copy number (≥ 3 hTERT gene copies/nucleus) was observed in 31 cases (48%). No statistical association existed between hTERT gene copy number and hTERT RNA expression or telomerase activity. However, a significant relationship was found between an increase in hTERT gene copy number and p53 protein accumulation (p = 0.002) and aneuploidy (p = 0.036). Only 4 tumors showed microsatellite instability, 3 of which had a normal hTERT gene copy number. The data indicated that the increased copy number of the hTERT gene in colorectal carcinoma was a result of genomic instability with no obvious consequence for telomerase activity levels.
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| 39. |
- Petersson, Fredrik, 1965-
(författare)
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Chronic gastritis in a sample of the general population : Helicobacter pylori infection, metaplastic transformation, epithelial proliferation, p53- and p21 expression and antral mucosal gastrin content with reference to gastric carcinoma development
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Infection with H. pylori is the main cause of chronic inflammation in the stomach. lt is strongly associated with benign ulcer disease and a risk factor for gastric carcinoma (GC). Different tophographical types of gastritis bear different risks for future development of GC. Mucosal changes, atrophy and intestinal metaplasia (IM) are known precancerous conditions.The aims of this thesis were to map out the prevalence of chronic gastritis, including different tophographical types, carditis and H. pylori infection in an adult Swedish general population sample. To determine the prevalence of atrophy and different types of IM and measure the mucosal proliferative activity (Ki-67), expression of p53 and p21 with immunohistochemistry. Furthermore, to determine plasma levels of gastrin and the content of G-cells in the antrum with immunohistochemistry measured with three different morphometrical methods.The prevalence of chronic gastritis was 50%. lt was associated with H. pylori infection in 87%. The prevalence of carditis was 55% and it was associated with local H. pylori infection in 70%. The most common type of gastritis was antrum predominant (44%) followed by pangastritis (37%) and corpus predominant (19%). The prevalence of atrophy (antrum and/or corpus) was 55% and it increased with age, as did the prevalence of IM, which was present in the antrum or corpus in 23% and in the cardia in 10%. Corresponding figures for the prevalence of type III IM was 4% and 1%, repspectively. In all locations there was a strong correlation between the occurrence of IM and both H. pylori infection and chronic inflammation. Chronic inflammation and H. pylori infection were associated with increased mucosal proliferation and expression of p53. Atrophy as well as IM were associated with increased expression of p53 in both the corpus and antrum. IM was associated with increased proliferation in the mucosa, as was atrophy in the corpus. The expression of p21 was low and not affected by infection or inflammation. Plasma levels of gastrin were increased in subjects with H. pylori infection and showed no correlation with the amount of antral G-cells. The three different methods for G-cell quantification correlated poorly.In conclusion,chronic gastritis and carditis in this sample of an adult Swedish general population were frequent and strongly associated with H. pylori infection. The prevalences of different gastritis types and mucosal changes associated with increased cancer risk were determined and the relationships between chronic gastritis/carditis and both increased mucosal proliferation and expression of p53 in all parts of the stomach were established. Increased plasma levels of gastrin among subejects with H. pylori infection were established, as was the lack of a correlation between circulating gastrin levels and the amount of G-cells in the antrum. Poor correlations between three different methods for G-cell quantification highlight a methodological problem.
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| 40. |
- Rutegård, Martin, et al.
(författare)
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Efficiency of Colorectal Cancer Surveillance in Patients With Ulcerative Colitis : 38 Years' Experience in a Patient Cohort From a Defined Population Area
- 2017
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Ingår i: Scandinavian Journal of Surgery. - : Sage Publications. - 1457-4969 .- 1799-7267. ; 106:2, s. 133-138
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: Ulcerative colitis increases the risk of developing colorectal cancer. Colonoscopic surveillance is recommended although there are no randomized trials evaluating the efficacy of such a strategy. This study is an update of earlier studies from an ongoing colonoscopic surveillance program.MATERIAL AND METHODS: All patients with ulcerative colitis were invited to the surveillance program that started in 1977 at Örnsköldsvik Hospital, located in the northern part of Sweden. Five principal endoscopists performed the colonoscopies and harvested mucosal sampling for histopathological evaluation. Some 323 patients from the defined catchment area were studied from 1977 to 2014. At the end of the study period, 130 patients, including those operated on, had had total colitis for more than 10 years.RESULTS: In total, 1481 colonoscopies were performed on 323 patients during the study period without any major complications. In all, 10 cases of colorectal cancer were diagnosed in 9 patients, of whom 1 died from colorectal cancer. The cumulative incidence of colorectal cancer was 1.4% at 10 years, 2.0% at 20 years, 3.0% at 30 years, and 9.4% at 40 years of disease duration, respectively. The standardized colorectal cancer incidence ratio was 3.01 (95% confidence interval: 1.42-5.91). Major surgery was performed on 65 patients; for 20 of these, the indication for surgery was dysplasia or colorectal cancer. Panproctocolectomy was performed in 43 patients.CONCLUSION: This study supports that colonoscopic surveillance is a safe and effective long-term measure to detect dysplasia and progression to cancer. The low numbers of colorectal cancer-related deaths in our study suggest that early detection of neoplasia and adequate surgical intervention within a surveillance program may reduce colorectal cancer mortality in ulcerative colitis patients.
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