scholarly journals Microsatellite Instability assessment in Black South African Colorectal Cancer patients reveal an increased incidence of suspected Lynch syndrome

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
M. McCabe ◽  
Y. Perner ◽  
R. Magobo ◽  
P. Magangane ◽  
S. Mirza ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Lynch Syndrome ◽  
Microsatellite Instability ◽  
Mutational Analysis ◽  
Statistical Tests ◽  
Biological Information ◽  
Protein Loss ◽  
Braf Mutations ◽  
Chi Square ◽  
Black South African

Abstract Microsatellite Instability (MSI) is a hallmark of colorectal cancer (CRC) and occurs in 15–16% of CRC. Molecular biological information of CRC in South Africa (SA) is largely unrecorded. This study was undertaken to determine the frequency of MSI, with particular reference to Lynch syndrome (LS) with a view to improve surveillance and prevention strategies. This was a retrospective study on CRC samples diagnosed between 2011–2015 at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH). Samples diagnosed between 2011–2012 were screened for MSI by PCR and mismatch repair (MMR) immunohistochemistry (IHC), and additional BRAFV600E mutational analysis performed. T-tests, Fischer’s exact and Chi square statistical tests were applied. Twelve percent of patients displayed MSI, with increased frequency in black (15%) versus other ethnic group (OEG) (8%) patients. MSI patients were significantly younger than microsatellite stable (MSS) patients, however when stratified by ethnicity, black patients were predominantly younger (median age: 47), with increased MSH2/6 loss, and no BRAF mutations. These findings suggest a large proportion of young black SA CRC patients develop via the LS pathway due to earlier age onset and predominant MSH2/6 protein loss. SA patients of other ethnicities appear to follow the more well established sporadic MSI pathway.

TUMOUR PATHOLOGY PREDICTS MICROSATELLITE INSTABILITY IN A POPULATION-BASED SERIES OF COLORECTAL CANCER CASES

2008 ◽  
Vol 31 (4) ◽  
pp. 12
Author(s):  
A J Hyde ◽  
D Fontaine ◽  
R C Green ◽  
M Simms ◽  
P S Parfrey ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Lynch Syndrome ◽  
Microsatellite Instability ◽  
Population Based ◽  
Pathological Features ◽  
Predictive Tool ◽  
Entire Cohort ◽  
Dna Mismatch ◽  
Bethesda Guidelines ◽  
Revised Bethesda Guidelines

Background: Lynch Syndrome is an autosomal dominant trait that accounts forapproximately 3% of all cases of colorectal cancer (CRC). It is caused by mutations in DNA mismatch repair (MMR) genes, most commonly MLH1 or MSH2. These MMR defects cause high levels of microsatellite instability (MSI-H) in the tumours. MSI testing of all CRCs to identify potential Lynch Syndrome cases is not practical, so the Bethesda Guidelines, which use clinical and pathological features, were created to identify those tumours most likely to be MSI-H^1. In 2007 Jenkins et. al. created MsPath, a tool based on the pathological features described in the rarely used 3^rd Bethesda criterion, to improve prediction of MSI-H tumours among CRC cases diagnosed before age 60 years^2. Methods: We collected a population-based cohort of 716 CRC cases diagnosed before age 75 years in Newfoundland. For each of these cases we collected family history, performed MSI analysis, and scored a number of pathological features for the purpose of evaluating the accuracy of the Bethesda Criteria and MsPath at predicting MSI-H tumours. Results: Our work validates the MsPath tool in the Newfoundland population for the same age group used to create the tool. We found it identified MSI-H cases with a sensitivity of 95% and specificity of 35% in our population of CRCcases diagnosed before age 60 years (n=290). We also tested this tool on our older population of CRCcases, diagnosed at ages 60 to 74 years (n=426). We found it to be at least as predictive in this population,with a sensitivity of 95% and a specificity of 42%. We then used our entire cohort (N=716) to compare MsPath with the other Bethesda criteria.Bethesda criteria 1, 2, 4 and 5 together predicted MSI-H cases with a sensitivity of 67% and a specificity of 51%. MsPath was better at identifying these cases, with a sensitivity of 95% and a specificity of 39%. Conclusions: We conclude that MsPath can be extended to include patients diagnosed with CRC before age 75 years. As well, we have found that MsPath is a better predictive tool than the Revised Bethesda Guidelines for identifying MSI-H cases within a population-based setting of colorectal cancer. References: 1. Umar, A. et. al. J Natl Cancer Inst 2004;96:261-8 2.Jenkins, M.A. et. al. Gastroenterology 2007;133:48-56

scholarly journals Combined BRAF and MEK Inhibition With Dabrafenib and Trametinib in BRAF V600–Mutant Colorectal Cancer

2015 ◽  
Vol 33 (34) ◽  
pp. 4023-4031 ◽  
Author(s):  
Ryan B. Corcoran ◽  
Chloe E. Atreya ◽  
Gerald S. Falchook ◽  
Eunice L. Kwak ◽  
David P. Ryan ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Protein Kinase ◽  
Partial Response ◽  
Microsatellite Instability ◽  
Mutational Analysis ◽  
Braf Inhibitor ◽  
Complete Response ◽  
Mitogen Activated Protein Kinase ◽  
Pik3ca Mutations ◽  
Mitogen Activated Protein

Purpose To evaluate dabrafenib, a selective BRAF inhibitor, combined with trametinib, a selective MEK inhibitor, in patients with BRAF V600–mutant metastatic colorectal cancer (mCRC). Patients and Methods A total of 43 patients with BRAF V600–mutant mCRC were treated with dabrafenib (150 mg twice daily) plus trametinib (2 mg daily), 17 of whom were enrolled onto a pharmacodynamic cohort undergoing mandatory biopsies before and during treatment. Archival tissues were analyzed for microsatellite instability, PTEN status, and 487-gene sequencing. Patient-derived xenografts were established from core biopsy samples. Results Of 43 patients, five (12%) achieved a partial response or better, including one (2%) complete response, with duration of response > 36 months; 24 patients (56%) achieved stable disease as best confirmed response. Ten patients (23%) remained in the study > 6 months. All nine evaluable during-treatment biopsies had reduced levels of phosphorylated ERK relative to pretreatment biopsies (average decrease ± standard deviation, 47% ± 24%). Mutational analysis revealed that the patient achieving a complete response and two of three evaluable patients achieving a partial response had PIK3CA mutations. Neither PTEN loss nor microsatellite instability correlated with efficacy. Responses to dabrafenib plus trametinib were comparable in patient-derived xenograft–bearing mice and the biopsied lesions from each corresponding patient. Conclusion The combination of dabrafenib plus trametinib has activity in a subset of patients with BRAF V600–mutant mCRC. Mitogen-activated protein kinase signaling was inhibited in all patients evaluated, but to a lesser degree than observed in BRAF-mutant melanoma with dabrafenib alone. PIK3CA mutations were identified in responding patients and thus do not preclude response to this regimen. Additional studies targeting the mitogen-activated protein kinase pathway in this disease are warranted.

scholarly journals Role of microsatellite instability-low as a diagnostic biomarker of Lynch syndrome in colorectal cancer

2014 ◽  
Vol 207 (10-12) ◽  
pp. 495-502 ◽  
Author(s):  
Eduardo Vilar ◽  
Maureen E. Mork ◽  
Amanda Cuddy ◽  
Ester Borras ◽  
Sarah A. Bannon ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Lynch Syndrome ◽  
Microsatellite Instability ◽  
Diagnostic Biomarker

scholarly journals Mutational Analysis of Patients With Colorectal Cancer in CALGB/SWOG 80405 Identifies New Roles of Microsatellite Instability and Tumor Mutational Burden for Patient Outcome

2019 ◽  
Vol 37 (14) ◽  
pp. 1217-1227 ◽  
Author(s):  
Federico Innocenti ◽  
Fang-Shu Ou ◽  
Xueping Qu ◽  
Tyler J. Zemla ◽  
Donna Niedzwiecki ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Microsatellite Instability ◽  
Metastatic Colorectal Cancer ◽  
Mutational Analysis ◽  
Gene Mutations ◽  
Phase Iii ◽  
First Line ◽  
Mutational Burden ◽  
Significant Difference ◽  
Tumor Mutational Burden

PURPOSE CALGB/SWOG 80405 was a randomized phase III trial that found no statistically significant difference in overall survival (OS) in patients with first-line metastatic colorectal cancer treated with chemotherapy plus either bevacizumab or cetuximab. Primary tumor DNA from 843 patients has been used to discover genetic markers of OS. PATIENTS AND METHODS Gene mutations were determined by polymerase chain reaction. Microsatellite status was determined by genotyping of microsatellites. Tumor mutational burden (TMB) was determined by next-generation sequencing. Cox proportional hazard models were used, with adjusting factors. Interaction of molecular alterations with either the bevacizumab or the cetuximab arms was tested. RESULTS Patients with high TMB in their tumors had longer OS than did patients with low TMB (hazard ratio [HR], 0.73 [95% CI, 0.57 to 0.95]; P = .02). In patients with microsatellite instability–high (MSI-H) tumors, longer OS was observed in the bevacizumab arm than in the cetuximab arm (HR, 0.13 [95% CI, 0.06 to 0.30]; interaction P < .001 for interaction between microsatellite status and the two arms). Patients with BRAF mutant tumors had shorter OS than did patients with wild-type (WT) tumors (HR, 2.01 [95% CI, 1.49 to 2.71]; P < .001). Patients with extended RAS mutant tumors had shorter OS than did patients with WT tumors (HR, 1.52 [95% CI, 1.26 to 1.84]; P < .001). Patients with triple-negative tumors (WT for NRAS/ KRAS/ BRAF) had a median OS of 35.9 months (95% CI, 33.0 to 38.8 months) versus 22.2 months (95% CI, 19.6 to 24.4 months ) in patients with at least one mutated gene in their tumors ( P < .001). CONCLUSION In patients with metastatic colorectal cancer treated in first line, low TMB, and BRAF and RAS mutations are negative prognostic factors. Patients with MSI-H tumors benefited more from bevacizumab than from cetuximab, and studies to confirm this effect of MSI-H are warranted.

scholarly journals Mismatch Repair Protein Loss as a Prognostic and Predictive Biomarker in Breast Cancers Regardless of Microsatellite Instability

2018 ◽  
Vol 2 (4) ◽  
Author(s):  
Nicola Fusco ◽  
Gianluca Lopez ◽  
Chiara Corti ◽  
Chiara Pesenti ◽  
Patrizia Colapietro ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Statistical Tests ◽  
Immune Checkpoint Blockade ◽  
Breast Cancers ◽  
Breast Cancer Patients ◽  
Protein Loss ◽  
Clinical Value ◽  
Msi Analysis

Abstract Background Breast cancers that harbor mismatch-repair (MMR) deficiency and/or microsatellite instability (MSI) might be sensitive to immune checkpoint blockade, but there are currently no specific guidelines for assessing MMR status in breast cancer. Here, we sought to define the clinical value of MMR immunohistochemistry (IHC) and MSI analysis in breast cancers. Methods We subjected 444 breast cancers to MMR IHC and MSI analysis. Cases were classified as MMR-proficient (pMMR), MMR-deficient (dMMR), and MMR-heterogeneous (hMMR) based on the loss of immunoreactivity; MSI was defined by instability in the five indicators recommended by the National Cancer Institute for endometrial and colorectal cancers. Correlation of MMR status with patients’ survival was assessed using the Kaplan-Meier estimator. Statistical tests were two-sided. Results Loss of MMR proteins was homogeneous (dMMR) in 75 patients (17%) and heterogeneous (hMMR) in 55 (12%). Among luminal breast cancers, there were similar frequencies of dMMR and hMMR tumors. Overall, the rate of discrepancy between IHC and MSI analysis was high (91%). Women with Luminal B-like dMMR carcinomas (n = 44) showed shorter overall survival (median = 77 months, range = 0–115 months) than those with pMMR (n = 205) or hMMR (n = 35) tumors (median = 84 months, range = 0–127 months) (P = .008). On the contrary, patients with estrogen receptor-negative breast cancers treated with chemotherapy lived longer in cases of dMMR (n = 9) than pMMR (n = 33) or hMMR (n = 7) tumors, with 87 months of median survival (range = 73–123 months) for the former compared with 79 months (range = 8–113 months) for the latter two categories (P < .001). Conclusions Immunohistochemistry and MSI are not interchangeable tests in breast carcinomas. MMR protein loss is a more common event than MSI and shows intra-tumor heterogeneity. MMR IHC allows the identification of clinically relevant subclasses of breast cancer patients, provided that multiple areas of the tumor are analyzed.

scholarly journals Methylation in p14ARF is Frequently Observed in Colorectal Cancer with Low-level Microsatellite Instability

2009 ◽  
Vol 37 (4) ◽  
pp. 1038-1045 ◽  
Author(s):  
K Kominami ◽  
T Nagasaka ◽  
HM Cullings ◽  
N Hoshizima ◽  
H Sasamoto ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Microsatellite Instability ◽  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Gene Promoters ◽  
Braf Mutations ◽  
Low Level ◽  
Methylguanine Dna Methyltransferase ◽  
High Level

Colorectal cancer (CRC) can be classified as high-level microsatellite instability (MSI-H), low-level MSI (MSI-L) and microsatellite stable (MSS) depending on levels of MSI. MSI-H CRC relies on a distinct molecular pathway due to the mismatch repair (MMR) deficiency and shows methylation in multiple gene promoters. The genetic pathway leading to MSI-L is unknown, although higher levels of promoter methylation are observed in this group compared with MSS CRCs. This study explored how promoter methylation affects MSI phenotype, by analysing the methylation status of eight CRC-related promoters, MSI phenotype and KRAS/BRAF mutations in a series of 234 CRCs. Promoter methylation of p14ARF was significantly related to MSI-L CRC with KRAS mutation. The MSI-H phenotype was related to methylation of MLH1 as expected, while the MSS phenotype was related to methylation of p16INK4a and O6-methylguanine-DNA methyltransferase, although this was not statistically significant. Thus, promoter methylation of p14ARF could be a significant alteration leading to CRC with MSI-L.

Use of immunohistochemical versus microsatellite analyses as markers for colorectal cancer

2017 ◽  
Vol 43 (2) ◽  
pp. 134-141
Author(s):  
Utku Tantoğlu ◽  
Seher Yüksel ◽  
Cihangir Akyol ◽  
Haldun Doğan ◽  
Nükhet Kutlay ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Lynch Syndrome ◽  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Immunohistochemical Analysis ◽  
Sporadic Colorectal Cancer ◽  
Molecular Tests ◽  
Antibody Panel ◽  
Mismatch Repair Proteins ◽  
Good Concordance

Abstract Objectives: Our aim was to determine how well immunohistochemical analysis identified colon cancer patients with microsatellite instability in Turkish patients. Material and methods: Subjects were patients that underwent surgery for colorectal cancer in our institution between 2006 and 2011. Patients were grouped as: (1) suspected Lynch syndrome (n=14), (2) familial colorectal cancer (n=14), and (3) sporadic colorectal cancer groups (n=14). Mismatch repair proteins were analyzed by a four antibody-panel immunohistochemistry. Microsatellite instability analysis was conducted on DNA samples using MSI-PCR followed by fragment analysis. Results: The immunohistochemistry and PCR results had good concordance in 35/42 patients. Both microsatellite instability and at least one mismatch repair protein deficiency were detected in 11 patients, and both microsatellite stability and normal expression of mismatch repair proteins were detected in 24 patients. Test results were discordant in seven of the patients. Conclusion: As it is not feasible to perform expensive molecular tests in healthcare units in many developing countries, the four antibody-panel immunohistochemistry is a reliable and affordable method for screening for colorectal cancer, including Lynch syndrome and sporadic cases when suspected.

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