scholarly journals Microsatellite instability, MMR gene expression and proliferation kinetics in colorectal cancer with famillial predisposition

2000 ◽  
Vol 6 (6) ◽  
pp. 902 ◽  
Author(s):  
Bao Ping Wu
2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Anna Pačínková ◽  
Vlad Popovici

The dysfunction of the DNA mismatch repair system results in microsatellite instability (MSI). MSI plays a central role in the development of multiple human cancers. In colon cancer, despite being associated with resistance to 5-fluorouracil treatment, MSI is a favourable prognostic marker. In gastric and endometrial cancers, its prognostic value is not so well established. Nevertheless, recognising the MSI tumours may be important for predicting the therapeutic effect of immune checkpoint inhibitors. Several gene expression signatures were trained on microarray data sets to understand the regulatory mechanisms underlying microsatellite instability in colorectal cancer. A wealth of expression data already exists in the form of microarray data sets. However, the RNA-seq has become a routine for transcriptome analysis. A new MSI gene expression signature presented here is the first to be valid across two different platforms, microarrays and RNA-seq. In the case of colon cancer, its estimated performance was (i) AUC = 0.94, 95% CI = (0.90 – 0.97) on RNA-seq and (ii) AUC = 0.95, 95% CI = (0.92 – 0.97) on microarray. The 25-gene expression signature was also validated in two independent microarray colon cancer data sets. Despite being derived from colorectal cancer, the signature maintained good performance on RNA-seq and microarray gastric cancer data sets (AUC = 0.90, 95% CI = (0.85 – 0.94) and AUC = 0.83, 95% CI = (0.69 – 0.97), respectively). Furthermore, this classifier retained high concordance even when classifying RNA-seq endometrial cancers (AUC = 0.71, 95% CI = (0.62 – 0.81). These results indicate that the new signature was able to remove the platform-specific differences while preserving the underlying biological differences between MSI/MSS phenotypes in colon cancer samples.


Cancers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 4449
Author(s):  
Pascale Palassin ◽  
Marion Lapierre ◽  
Samuel Pyrdziak ◽  
Antoine Wagner ◽  
Régine Stehle ◽  
...  

Microsatellite instability (MSI) is related to the alteration of mismatch repair (MMR) genes and plays a key role in colorectal cancer (CRC) pathogenesis. We previously reported that the transcription factor Nuclear Receptor Interacting Protein 1 (NRIP1) is involved in sporadic intestinal tumorigenesis. The aim of this study was to decipher its role in MSI CRC. By using different mouse models and engineered cell lines, we demonstrated that NRIP1 increased MSH2 and MSH6 MMR gene transcription and mRNA/protein levels. In human CRC cells, NRIP1 expression was associated with decreased MSI and the hypermutator phenotype, and with resistance to chemotherapy drugs. Using a cohort of 194 CRC patients, we detected in 22% of the cases a MSI-induced frameshift mutation in the NRIP1 coding sequence. This genetic alteration generates a truncated protein with a dominant negative activity that increased human CRC cell proliferation and impaired the regulation of MSH2 and MSH6 gene expression. Moreover, the NRIP1 mutant correlated with a decreased overall survival of patients with advanced CRC, especially when MLH1-deficient. By decreasing the expression of MSH2 and MSH6 gene expression, the NRIP1 variant may amplify MLH1-dependent CRC progression and behave as a new prognostic marker of advanced MSI CRC.


2002 ◽  
Vol 20 (5) ◽  
pp. 1203-1208 ◽  
Author(s):  
Mario Scartozzi ◽  
Francesca Bianchi ◽  
Saverio Rosati ◽  
Eva Galizia ◽  
Annalisa Antolini ◽  
...  

PURPOSE: The relationship between germ-line mutations of hMSH2 and hMLH1, microsatellite instability (MSI), and loss of DNA mismatch repair (MMR) gene expression were studied to formulate an effective selection protocol for patients with suspected hereditary nonpolyposis colorectal cancer who should be offered genetic testing. PATIENTS AND METHODS: Patients eligible for germ-line analysis of hMLH1 and hMSH2 were selected. Tumor specimens were obtained to assess MSI and loss of MMR gene expression. RESULTS: Among 37 patients who participated in the study, two hMSH2 and two hMLH1 missense mutations (11%) were detected, none of which was found in a panel of 60 healthy volunteers. High MSI was found in five tumors (19%) and low MSI in 10 tumors (39%); 12 tumors (46%) were microsatellite stable. Four tumors demonstrated loss of hMLH1, and three tumors demonstrated loss of hMSH2 protein expression. CONCLUSION: No relationship was found between MMR gene mutations and MSI; low or no MSI was found in the four patients with germ-line mutations, and none of the five patients with high MSI demonstrated abnormalities of MMR genes. On the contrary, loss of hMLH1 or hMSH2 expression was found in the tumors from three of the four patients demonstrating germ-line mutations. These data suggest that germ-line mutations of the MMR gene can occur in people with MSI-negative tumors. Sensitive clinical criteria and the study of MMR gene expression may be useful to identify this subset of patients.


Endoscopy ◽  
2004 ◽  
Vol 36 (05) ◽  
Author(s):  
K Collins ◽  
GA Doherty ◽  
MR Sweeney ◽  
SM Byrne ◽  
AA Aftab ◽  
...  

2008 ◽  
Vol 31 (4) ◽  
pp. 12
Author(s):  
A J Hyde ◽  
D Fontaine ◽  
R C Green ◽  
M Simms ◽  
P S Parfrey ◽  
...  

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


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