| 11. |
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| 12. |
- Joost, Patrick, et al.
(författare)
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Efficient and reproducible identification of mismatch repair deficient colon cancer : Validation of the MMR index and comparison with other predictive models
- 2013
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Ingår i: BMC Clinical Pathology. - : Springer Science and Business Media LLC. - 1472-6890. ; 13:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Background: The identification of mismatch-repair (MMR) defective colon cancer is clinically relevant for diagnostic, prognostic and potentially also for treatment predictive purposes. Preselection of tumors for MMR analysis can be obtained with predictive models, which need to demonstrate ease of application and favorable reproducibility. Methods. We validated the MMR index for the identification of prognostically favorable MMR deficient colon cancers and compared performance to 5 other prediction models. In total, 474 colon cancers diagnosed ≥ age 50 were evaluated with correlation between clinicopathologic variables and immunohistochemical MMR protein expression. Results: Female sex, age ≥60 years, proximal tumor location, expanding growth pattern, lack of dirty necrosis, mucinous differentiation and presence of tumor-infiltrating lymphocytes significantly correlated with MMR deficiency. Presence of at least 4 of the MMR index factors identified MMR deficient tumors with 93% sensitivity and 76% specificity and showed favorable reproducibility with a kappa value of 0.88. The MMR index also performed favorably when compared to 5 other predictive models. Conclusions: The MMR index is easy to apply and efficiently identifies MMR defective colon cancers with high sensitivity and specificity. The model shows stable performance with low inter-observer variability and favorable performance when compared to other MMR predictive models.
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| 13. |
- Klarskov, Louise, et al.
(författare)
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Interobserver variability in the evaluation of mismatch repair protein immunostaining
- 2010
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Ingår i: Human Pathology. - : Elsevier BV. - 1532-8392 .- 0046-8177. ; 41:10, s. 1387-1396
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Tidskriftsartikel (refereegranskat)abstract
- Immunohistochemical staining for mismatch repair proteins has during recent years been established as a routine analysis in many pathology laboratories with the aim to identify tumors linked to the hereditary nonpolyposis colorectal cancer syndrome. Despite widespread application, data on reliability are lacking. We therefore evaluated interobserver variability among 6 pathologists, 3 experienced gastrointestinal pathologists and 3 residents. In total, 225 immunohistochemically stained colorectal cancers were evaluated as having normal, weak, loss of, or nonevaluable mismatch repair protein staining. Full consensus was achieved in 51% of the stainings for MLH1, 61% for PMS2, 83% for MSH2, and 45% for MSH6. Weak stainings were the main cause of reduced consensus, whereas contradictory evaluations with normal as well as loss of staining were reported in 2% to 6% of the tumors. Interobserver variability was considerable, though experienced pathologists and residents reached the same level of consensus. Because results from immunohistochemical mismatch repair protein stainings are used for decisions on mutation analysis and as an aid in the interpretation of gene variants of unknown significance in hereditary nonpolyposis colorectal cancer, the interobserver variability identified highlights the need for quality assessment programs, including guidelines for classification of different expression patterns. (C) 2010 Elsevier Inc. All rights reserved.
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| 14. |
- Malander, Susanne, et al.
(författare)
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The contribution of the hereditary nonpolyposis colorectal cancer syndrome to the development of ovarian cancer.
- 2006
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Ingår i: Gynecologic Oncology. - : Elsevier BV. - 1095-6859 .- 0090-8258. ; 101:2, s. 238-243
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Ovarian cancer has one of the highest fractions of hereditary cases. The hereditary breast and ovarian cancer syndrome, primarily due to mutations in BRCA1 and BRCA2, is the main cause of heredity, but also the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome confers an increased risk of ovarian cancer. In order to clarify the contribution of HNPCC to the development of ovarian cancer, we collected data on family history of cancer and characterized MMR function in a consecutive series of 128 tumors unselected for age at diagnosis and previously characterized for BRCA gene mutations. Methods. Expression of the MMR proteins MLH1 PMS2, MSH2, and MSH6 was analyzed by immunohistochemistry using tissue microarray sections. Tumors with reduced staining or loss of staining were also analyzed for microsatellite instability (MSI). Results. Loss of MMR protein expression was identified in 3 ovarian cancers, all of which had a MSI-high phenotype. DNA sequence analysis revealed disease-causing germline mutations (deletions of exons 4-6 in MLHI and a 1-nucleotide deletion in exon 5 of MSH6) in two patients diagnosed at ages 40 and 49 years, both of whom had family histories suggestive of HNPCC. The genetic defect in the third case, which was a 47-year old woman without knowledge about her family history with loss of MLH1/PMS2 expression in the tumor tissue, remains elusive. A family history suggestive of HNPCC was identified in an additional case, but this tumor showed normal, retained MMR protein expression and a microsatellite stable phenotype. Conclusions. About 2% of ovarian cancer is caused by germline mutations in the MMR-genes, a minor proportion as compared to the contribution of the BRCA-genes (11% in the present series). However, identification of HNPCC patients is important since it allows inclusion of high-risk individuals into control programs aimed at preventing the more frequent colorectal and endometrial cancers. Tumors within the HNPCC-spectrum should therefore be included when recording a family history of cancer among patients diagnosed with ovarian cancer. (c) 2005 Elsevier Inc. All rights reserved.
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| 15. |
- Planck, Maria, et al.
(författare)
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Cytogenetic aberrations and heterogeneity of mutations in repeat-containing genes in a colon carcinoma from a patient with hereditary nonpolyposis colorectal cancer.
- 2002
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Ingår i: Cancer Genetics and Cytogenetics. - 0165-4608. ; 134:1, s. 46-54
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Tidskriftsartikel (refereegranskat)abstract
- The majority of tumors from patients affected by hereditary nonpolyposis colorectal cancer (HNPCC) exhibit a mutator phenotype characterized by widespread microsatellite instability (MSI) and somatic mutations in repeated sequences in several cancer-associated genes. An inverse relationship between MSI and chromosomal instability (CIN) has been demonstrated and HNPCC-associated tumors are generally characterized by diploid or near-diploid cells with few or no chromosomal rearrangements. We have studied MSI, somatic mutations in repeat-containing genes, DNA-ploidy, and cytogenetic aberrations in a colon carcinoma from a patient with a germline MLH1 mutation. Mutations in coding repeats were assessed in 10 macroscopically separate areas of the primary tumor and in two lymph nodes. Some of the genes studied (E2F4, MSH3, MSH6, TCF4, and TGFBRII) showed a consistent lack of mutations, whereas others (BAX, Caspase-5 and IGFIIR) displayed alterations in some tumor regions but not in others. The tumor had DNA-index 1.1-1.2 and a stable, aberrant karyotype with extra copies of chromosomes 7 and 12 and the structural aberrations i(1q), der(20)t(8;20), and der(22)t(1;22). The finding of CIN, MSI, and somatic mutations in coding repeats in this tumor suggests that these phenomena may act together in HNPCC tumorigenesis. Furthermore, the observed intratumoral heterogeneity of mutations in coding repeats implies these changes occur late in tumorigenesis and, thus, probably play a role in tumor progression rather than initiation.
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| 16. |
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| 17. |
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| 18. |
- Robinson, Kristina Lagerstedt, et al.
(författare)
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Lynch syndrome (hereditary nonpolyposis colorectal cancer) diagnostics
- 2007
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 1460-2105 .- 0027-8874. ; 99:4, s. 291-299
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Tidskriftsartikel (refereegranskat)abstract
- Background Preventive programs for individuals who have high lifetime risks of colorectal cancer may reduce disease morbidity and mortality. Thus, it is important to identify the factors that are associated with hereditary colorectal cancer and to monitor the effects of tailored surveillance. In particular, patients with Lynch syndrome, hereditary nonpolyposis colorectal cancer (HNPCC), have an increased risk to develop colorectal cancer at an early age. The syndrome is explained by germline mutations in DNA mismatch repair (MMR) genes, and there is a need for diagnostic tools to preselect patients for genetic testing to diagnose those with HNPCC. Methods Patients (n = 112) from 285 families who were counseled between 1990 and 2005 at a clinic for patients at high risk for HNPCC were selected for screening to detect mutations in MMR genes MLH1, MSH2, MSH6, and PMS2 based on family history, microsatellite instability (MSI), and immunohistochemical analysis of MMR protein expression. Tumors were also screened for BRAF V600E mutations; patients with the mutation were considered as non-HNPCC. Results Among the 112 patients who were selected for screening, 69 had germline MMR mutations (58 pathogenic and 11 of unknown biologic relevance). Sixteen of the 69 mutations (23%) were missense mutations. Among patients with MSI-positive tumors, pathogenic MMR mutations were found in 38 of 43 (88%) of patients in families who met Amsterdam criteria and in 13 of 22 (59%) of patients in families who did not. Among patients with MSI-negative tumors, pathogenic MMR mutations were found in 5 of 17 (29%) of families meeting Amsterdam criteria and in 1 of 30 (3%) of non-Amsterdam families with one patient younger than age 50 years. In three patients with MSI-negative tumors who had pathogenic mutations in MLH1 or MSH6, immunohistochemistry showed loss of the mutated protein. Conclusion Our findings suggest that missense MMR gene mutations are common in HNPCC and that germline MMR mutations are also found in patients with IVISI-negative tumors.
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| 19. |
- Therkildsen, Christina, et al.
(författare)
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Gain of chromosomal region 20q and loss of 18 discriminates between Lynch syndrome and familial colorectal cancer
- 2013
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 1879-0852 .- 0959-8049. ; 49:6, s. 1226-1235
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Tidskriftsartikel (refereegranskat)abstract
- Lynch syndrome and familial colorectal cancer type X, FCCTX, represent the two predominant colorectal cancer syndromes. Whereas Lynch syndrome is clinically and genetically well defined, the genetic cause of FCCTX is unknown and genomic differences between Lynch syndrome and FCCTX tumours are largely unknown. We applied array-based comparative genomic hybridisation to 23 colorectal cancers from FCCTX with comparison to 23 Lynch syndrome tumours and to 45 sporadic colorectal cancers. FCCTX tumours showed genomic complexity with frequent gains on chromosomes 20q, 19 and 17 and losses of 18, 8p and 15. Gain of genetic material in two separate regions encompassing, 20q12-13.12 and 20q13.2-13.32, was identified in 65% of the FCCTX tumours. Gain of material on chromosome 20q and loss on chromosome 18 significantly discriminated colorectal cancers associated with FCCTX from Lynch syndrome, which likely signifies different preferred tumourigenic pathways. (C) 2012 Elsevier Ltd. All rights reserved.
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| 20. |
- Webb, Charlotta, et al.
(författare)
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Accuracy in Celiac Disease Diagnostics by Controlling the Small-bowel Biopsy Process
- 2011
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Ingår i: JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION. - : Lippincott, Williams and Wilkins. - 0277-2116 .- 1536-4801. ; 52:5, s. 549-553
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: In a Swedish celiac disease screening study (Exploring the Iceberg of Celiacs in Sweden), we systematically reviewed the clinical diagnostic procedures with the aim to evaluate the diagnostic accuracy and to take advantage of lessons learned for improving diagnostic routines. Materials and Methods: A school-based celiac disease screening study involving 5 Swedish centers, with 10,041 invited 12-year-olds with 7567 consenting participation. All 192 children with elevated serological markers were recommended to undergo small-bowel biopsy, performed and evaluated according to local clinical routines. All of the mucosal specimens were reevaluated by 1 and, when needed, 2 expert pathologists to reach diagnostic consensus. Results: Small-bowel biopsies were performed in 184 children: 130 by endoscopy and 54 by suction capsule. Endoscopic biopsies were inconclusive in 0.6%, compared with 7.4% of biopsies by suction capsule. A patchy enteropathy was found in 9.1%. Reevaluation by the expert pathologist resulted in 6 additional cases with celiac disease and 1 cleared. Sixteen children with normal or inconclusive biopsies, 4 after endoscopy, and 12 after suction capsule were endoscopically rebiopsied, resulting in another 8 cases. The celiac disease prevalence of 30 of 1000 (95% confidence interval 26-34) was not statistically different from that previously reported. Conclusions: The present review revealed the importance of controlling each step of the diagnostic procedure. Several cases would have been missed by relying only on local routines. To improve the quality of childhood celiac disease diagnostics, we recommend multiple endoscopic biopsies from both proximal and distal duodenum and standardized evaluation by a pathologist with good knowledge of celiac disease.
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