| 1. |
- Andreasson, Håkan, et al.
(författare)
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Histopathological classification of pseudomyxoma peritonei and the prognostic importance of PINCH protein
- 2012
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Ingår i: Anticancer Research. - : International Institute of Anticancer Research (IIAR). - 0250-7005 .- 1791-7530. ; 32:4, s. 1443-1448
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Tidskriftsartikel (refereegranskat)abstract
- AIM: The aims of this study were i) to assess a new and more detailed histopathological classification and to analyze concordance between pathologists in the histopathological classification of pseudomyxoma peritonei (PMP); ii) to analyze the expression in the stroma of the particularly interesting new cysteine-histidine (PINCH) protein and its prognostic importance in PMP.MATERIALS AND METHODS: Surgical specimens from 81 patients, classified according to the Ronnett et al histopathological classification were compared to a new system with four groups ranging from indolent to aggressive growth patterns. PINCH protein expression was analyzed and was related to clinical variables.RESULTS: The new four-group classification provided better prognostic information than the classification according to Ronnett et al. (p=0.04). Expression of the PINCH protein in the stroma was found in 83% of the cases and was associated with high tumor burden (p=0.002) and a poor prognosis (p=0.04).CONCLUSION: The proposed new PMP classification system may provide additional prognostic information. PINCH protein is expressed in PMP and has prognostic information.
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| 2. |
- Dahlin, Anna, 1979-
(författare)
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The CpG island methylator phenotype in colorectal cancer : studies on risk and prognosis
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Colorectal cancer (CRC) is the second most common malignancy in developed countries. The mortality is high, with nearly half of patients dying from the disease. The primary treatment of CRC is surgery, and decisions about additional treatment with chemotherapy are based mainly on tumor stage. Novel prognostic markers that identify patients at high risk of recurrence and cancer-related death are needed. The development of CRC has been described in terms of two different pathways; the microsatellite instability (MSI) and chromosomal instability (microsatellite stable, MSS) pathway. More recently, the CpG island methylator phenotype (CIMP), characterized by frequent DNA hypermethylation, has been described as an alternative pathway of tumorigenesis. The event of DNA methylation is dependent on one-carbon metabolism, in which folate and vitamin B12 have essential functions. The purpose of this thesis was to study CIMP in CRC. The specific aims were to investigate the potential role of components of one-carbon metabolism as risk factors for this subgroup of tumors, and the prognostic importance of CIMP status, taking into consideration important confounding factors, such as MSI and tumor-infiltrating T cells. Methods CRC cases and referents included in the Northern Sweden Health and Disease Study (NSHDS, 226 cases and 437 referents) and CRC cases in the Colorectal Cancer in Umeå Study (CRUMS, n=490) were studied. Prediagnostic plasma concentrations of folate and vitamin B12 were analyzed in NSHDS. In both study groups, CIMP status was determined in archival tumor tissue by real-time quantitative PCR using an eight-gene panel (CDKN2A, MLH1, CACNA1G, NEUROG1, RUNX3, SOCS1, IGF2 and CRABP1). MSI screening status and the density of tumor-infiltrating T cells were determined by immunohistochemistry. Results An inverse association was found between plasma concentrations of vitamin B12 and rectal, but not colon, cancer risk. We also found a reduced risk of CIMP-high and CIMP-low CRC in study subjects with the lowest levels of plasma folate. We found that patients with CIMP-low tumors in both NSHDS and CRUMS had a poorer prognosis compared with CIMP-negative, regardless of MSI screening status. We also found that MSS CIMP-high patients had a poorer prognosis compared with MSS CIMP-negative. The density of tumor-infiltrating T cells and CIMP status were both found to be independent predictors of CRC patient prognosis. A particularly poor prognosis was found in patients with CIMP-low tumors poorly infiltrated by T cells. In addition, the density of T cells appeared to be more important than MSI screening status for predicting CRC patient prognosis. Conclusion Rather than being one disease, CRC is a heterogeneous set of diseases with respect to clinico-pathological and molecular characteristics. We found that the association between risk and plasma concentration of vitamin B12 and folate depends on tumor site and CIMP status, respectively. Patient prognosis was found to be different depending on CIMP and MSI screening status, and the density of tumor-infiltrating T cells.
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| 3. |
- Nilsson, Torbjorn K., et al.
(författare)
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DNA methylation of the p14(ARF), RASSF1A and APC1A genes as an independent prognostic factor in colorectal cancer patients
- 2013
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Ingår i: International Journal of Oncology. - : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 42:1, s. 127-133
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Tidskriftsartikel (refereegranskat)abstract
- We quantitated the methylated fraction of CpG sites in the promoter regions of O-6-MGMT, p14(ARF), p16(INK4a), RASSF1A and APC1A in tumor tissue from patients with colorectal cancer (CRC) in order to determine if promoter hypermethylation of any of these genes predicts survival. DNA was isolated from 111 primary CRC and 46 matched normal colorectal mucosa samples from the same patients, obtained at primary surgery and DNA methylation was examined by Pyrosequencing (R). Follow-up time was up to 20 years. Patients showed partial promoter methylation in the following frequencies: O-6-MGMT, 34%; p14(ARF), 29%; p16(INK4a), 28%; RASSF1A, 14%; and APC1A, 27%. Normal mucosa was always unmethylated. CRC patients with methylated p14(ARF). gene promoter had significantly worse prognosis (p=0.036), whereas those with methylated O-6-MGMT had significantly better prognosis through the first 60 months post-treatment (RR 0.36; p=0.023). Methylation of one or more of the genes from the set p14(ARF), RASSF1A and APC1A, was significantly (p=0.021) associated with worse prognosis even adjusting for tumor stage and differentiation (RR 2.2, p=0.037). Thus, DNA methylation of the p14(ARF), RASSF1A and APC1A genes, diagnosed by Pyrosequencing, defines a poor prognosis subset of CRC patients independently of both tumor stage and differentiation. O-6-MGMT methylation may play a protective role.
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