Defective mismatch repair proteins and microsatellite instability in young Mexican patients with colorectal cancer.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e14708-e14708
Author(s):  
Arturo Quintanilla Guzman ◽  
Arturo Luevano Gonzalez ◽  
Augusto Rojas Martinez ◽  
Juan Pablo Flores Gutierrez ◽  
Juan Francisco Gonzalez Guerrero ◽  
...  
Keyword(s):  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Young Patients ◽  
Gene Promoter ◽  
Braf V600e Mutation ◽  
Braf V600e ◽  
Braf Mutations ◽  
Dna Repair Mechanisms ◽  
Repair Mechanisms ◽  
Msi Analysis

e14708 Background: Colorectal carcinoma (CRC) is prevalent malignancy and a third of the cases affect young patients. 15% of CRC have microsatellite instability (MSI) due to disruptions in mismatch repair (MMR) genes, like germline mutations (3%) and hypermethylation of the MLH1 gene promoter associated to the BRAF V600E mutation (12%). The aim of this work was to assess MMR abnormalities in tumors of Mexican CRC patients under 50 years old. Methods: CRC paraffin-embedded tissues of 47 patients with available demographic/clinical data were studied by immunohistochemistry (IHC) for MLH1/MSH2, qPCR with specific probes/sequencing for the BRAF V600E mutation, and conventional PCR (5 markers) for MSI analysis. Results: Female:Male ratio was 0.81:1. Most of the cases were classified as TNM Stage II, were located in the cecum, invaded the serous coat, and showed intestinal-type histology. 20 samples showed alterations in MMR protein expression. MLH1, MSH2, and combined deficiency of both proteins were detected in 17, 4, and 4 tumors, respectively. No BRAF mutations were detected. MSI analysis restricted to the 20 altered IHC samples showed MSI in 10 tumors (3 MSI-low and 7 MSI-high tumors). The four cases with MLH1/MSH2 deficiency, showed MSI-high pattern. Conclusions: We found 42.6% cases with defective MMR expression. No epigenetic abnormalities associated to BRAF V600E mutation were registered. The lack of MSI in ten tumors with deficient MMR may be due to alternate DNA repair mechanisms. Acknowledgments. Work supported by the CHIBCHA Project (European Commission7FP grant #223678).

Microsatellite Instability, Mismatch Repair Deficiency, and BRAF Mutation in Treatment-Resistant Germ Cell Tumors

2009 ◽  
Vol 27 (13) ◽  
pp. 2129-2136 ◽  
Author(s):  
Friedemann Honecker ◽  
Hendrik Wermann ◽  
Frank Mayer ◽  
Ad J.M. Gillis ◽  
Hans Stoop ◽  
...  
Keyword(s):  
Germ Cell ◽  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Braf Mutation ◽  
Cisplatin Resistance ◽  
Germ Cell Tumors ◽  
Braf V600e ◽  
Braf Mutations ◽  
Kras Mutations ◽  
Mmr Deficiency

Purpose Mismatch repair (MMR) deficiency and microsatellite instability (MSI) are associated with cisplatin resistance in human germ cell tumors (GCTs). BRAF mutation (V600E) is found in MSI colorectal cancers. The role of RAS/RAF pathway mutations in GCT treatment response is unknown. Patients and Methods Two patient cohorts were investigated: 100 control GCTs (50 seminomas and 50 nonseminomas) and 35 cisplatin-based chemotherapy-resistant GCTs. MMR proteins were analyzed by immunohistochemistry, and eight microsatellite loci were examined for MSI. Tumors were assessed for specific BRAF and KRAS mutations. Results Resistant tumors showed a higher incidence of MSI than controls: 26% versus 0% in two or more loci (P < .0001). All resistant tumors were wild-type KRAS, and two controls (2%) contained a KRAS mutation. There was a significantly higher incidence of BRAF V600E mutation in resistant tumors compared with controls: 26% versus 1% (P < .0001). BRAF mutations were highly correlated with MSI (P = .006), and MSI and mutated BRAF were correlated with weak or absent staining for hMLH1 (P = .017 and P = .008). Low or absent staining of hMLH1 was correlated with promoter hypermethylation (P < .001). Tumors lacking expression of hMLH1 or MSH6 were significantly more frequent in resistant GCTs than in controls (P = .001 and 0.0036, respectively). Within the subgroup of resistant tumors, patients with MSI showed a trend to longer progression-free survival (P = .068). Conclusion We report for the first time a correlation between a gene mutation—BRAF V600E—and cisplatin resistance in nonseminomatous GCTs. Furthermore, a correlation between MMR deficiency, MSI, and treatment failure is confirmed.

scholarly journals BRAF Mutations as Actionable Targets: A Paradigm Shift in the Management of Colorectal Cancer and Novel Avenues

2021 ◽  
pp. OP.21.00160
Author(s):  
Ibrahim Halil Sahin ◽  
Jim Klostergaard
Keyword(s):  
Colorectal Cancer ◽  
Mismatch Repair ◽  
Growth Factor Receptor ◽  
Braf V600e Mutation ◽  
Braf V600e ◽  
Class I ◽  
Molecular Characteristics ◽  
Braf Mutations ◽  
Therapy Choice ◽  
Checkpoint Inhibitor Therapy

BRAF mutations in colorectal cancer have been studied over the past several decades. BRAF V600E mutation, a class I mutation, is the most common oncogenic BRAF alteration in colorectal cancer. Until recently, the BRAF V600E mutation was not among actionable genes for colorectal cancer. However, recent discoveries have revealed therapeutic opportunities. The BRAF with or without MEK inhibition combined with epidermal growth factor receptor–directed therapy was recently found to be an effective therapy choice for patients with advanced-stage BRAF V600–mutant colorectal cancer. However, it is essential to distinguish patients with BRAF V600E–mutant mismatch repair–deficient colorectal cancer from those with mismatch repair–proficient colorectal cancer, as immune checkpoint inhibitor therapy is more appealing in this subset of patients with colorectal cancer. This review article discusses the molecular characteristics of class I, II, and III BRAF mutants and their impact on the clinical behavior of colorectal cancer. We also review the recent progress in the targetability of BRAF mutations in colorectal cancer, which has led to changes in clinical practice and elaborates on innovative therapeutic approaches to enhance the efficacy of BRAF-targeting therapies, to achieve more durable responses.

scholarly journals Hereditary non-polyposis colorectal cancer is predicted to contribute towards colorectal cancer in young South African blacks

2009 ◽  
Vol 105 (1/2) ◽  
Author(s):  
L. Cronjé ◽  
P.J. Becker ◽  
A.C. Paterson ◽  
M. Ramsay
Keyword(s):  
Colorectal Cancer ◽  
South Africa ◽  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Braf V600e ◽  
Cancer Tissue ◽  
Braf Mutations ◽  
Tissue Samples ◽  
Molecular Features ◽  
Black Patients

A disproportionately large number of young (less than 50 years) black patients present with colorectal cancer (CRC) in South Africa. Although a phenomenon previously described elsewhere in Africa, its specific molecular basis, whether sporadic or hereditary, has not been established. Molecular analysis of these tumours could link them to the features known to be associated with specific types of hereditary colorectal cancer, specifically through examination of levels of microsatellite instability, promoter methylation and the presence or absence of KRAS and BRAF mutations. The molecular features of cancer tissue samples from 44 CRC cases of black and white patients in South Africa were accordingly retrospectively analysed without knowledge of family history. Compared with samples from older blacks (>50 years), those from young black patients presented more often with a low methylation phenotype (CIMP-L) and high levels of microsatellite instability (MSI-H). Furthermore, as determined by real-time PCR using probe technology, the tissues from 35% of young blacks showed mutations within exon 1 of the KRAS gene. The BRAF-V600E mutation was only evident in the case of a single young black patient. Based on these results it seems likely that a proportion of CRC cases in young black patients from South Africa develop through the accumulation of mutations resulting in a mismatch repair deficiency linked to MSI-H and, possibly, germline mutations in the mismatch repair genes. The features in these patients are consistent with a diagnosis of the Hereditary Non-Polyposis Colorectal Cancer (HNPCC) syndrome. This finding has important implications for patient management and suggests that family members may be at high risk for CRC.

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.

Analysis of BRAF, NRAS, cKIT, and EGFR alterations in melanoma lung metastases.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e19033-e19033
Author(s):  
Alessandra Ulivieri ◽  
Giuseppe Cardillo ◽  
Liborio Manente ◽  
Andrea Petricca Mancuso ◽  
Leonardo Vigna ◽  
...  
Keyword(s):  
Lung Metastases ◽  
Direct Sequencing ◽  
Primary Melanoma ◽  
High Response Rate ◽  
Braf V600e Mutation ◽  
Braf V600e ◽  
Fish Analysis ◽  
Braf Mutations ◽  
Curative Intent ◽  
Free Survival

e19033 Background: About 25% of pts will eventually develop lung metastases from primary melanoma. Activating mutations in BRAF, NRAS, CKIT and EGFR genes are involved in melanoma progression. Trials with drugs targeting oncogenic BRAF in melanoma have shown that a V600E mutation may identify a subgroup of pts with a high response rate. Methods: We analysedtheprevalence of BRAF, NRAS and CKIT mutations by direct sequencing and of EGFR copy number alterations by FISH, in pts affected by melanoma lung metastases, and explored their correlation with lung metastasis-free survival (LMFS) and post surgical progression-free survival (psPFS). Results: Over 10 years, 33 cases of pts with melanoma lung metastases were diagnosed at our institution, of which 22 underwent surgery with curative intent. The mean age was 64 years, and 19 (57.5%) were male. 51% carried a BRAF V600E mutation while 18% had a NRAS codon 61 mutation. The two events were mutually exclusive. No alterations were observed in exon 11 of the CKIT gene. FISH analysis indicated an EGFR low amplification in 3 cases and chromosome 7 polysomy in 13 cases. The presence of a BRAF V600E mutation was associated with a longer LMFS (median 6.1 vs 4.4 years, p<0.05), but it had no impact on psPFS (26.9 vs 29.6 months, p=0.6). NRAS mutations were associated with a reduction in both LMFS (3.7 years vs 4.7 years, p = 0.008) and, more significantly, in psPFS (12,5 months vs 41,1 months, p = 0.005; hazard ratio, 2.7). Conclusions: The frequency of mutations in BRAF (51%) and NRAS (18%) observed in lung metastatic melanomas was similar to the rates reported in other metastatic sites. BRAF mutations don't appear to be related with a more aggressive clinical course, while NRAS might be an independent negative prognostic factor after resection of melanoma lung metastases. The presence of BRAF mutations should be tested in melanoma lung metastases to identify the patients eligible for anti BRAF targeted therapy.

scholarly journals Frequency of Mismatch Repair Protein (MMRP) Deficiency among Young Jordanians Diagnosed with Colorectal Carcinoma (CRC)

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bayan Maraqa ◽  
Ghassan Al-Shbool ◽  
Osama Abu-Shawer ◽  
Mamoun Souleiman ◽  
Osama Alshakhatreh ◽  
...  
Keyword(s):  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Positive Family History ◽  
Young Patients ◽  
Immunohistochemical Analysis ◽  
Cancer Center ◽  
Repair Protein ◽  
Pathologic Features ◽  
Mismatch Repair Protein ◽  
Expression Loss

Purpose. Microsatellite instability (MSI) caused by mismatch repair protein (MMRP) deficiency is detected in 15% of sporadic colorectal cancers (CRCs). Our aim is to investigate the frequency of MMRP deficiency in young CRC patients, using immunohistochemical analysis. Methods. This study targeted cases of CRC at King Hussein Cancer Center from 2004 until 2012 in patients 45 years of age or younger at the time of diagnosis. Clinicopathological data was obtained from 155 patients’ records. Immunohistochemistry for MLH1, MSH2, PMS2, and MSH6 proteins was performed on paraffin-embedded tissue containing carcinoma. Results. The median age of patient at diagnosis was 38 years. A total of 29 (19%) cases showed deficient MMRP(dMMRP)expression. Loss of expression of PMS2 was seen in 17 cases, 12 cases of which showed loss of MLH1 expression. Loss of expression of MSH6 was seen in 10 cases, 9 of which showed loss of MSH2 expression. One case (3.4%) showed loss of all four MMR proteins, and another case (3.4%) showed loss of PMS2/MLH1 and MSH6. There was a significant association between abnormal MMR protein expression and tumor location proximal to splenic flexure (p value 0.000), pathologic features suggestive of microsatellite instability (p value 0.000), P53 negativity (p value 0.000), and stage (p value 0.02). Patients with dMMRP CRC appeared to have a significantly better overall survival compared to patients with proficient MMRP(pMMRP)(p value 0.02). Loss of MSH2/MSH6 was significantly associated with positive family history of cancer (p value = 0.020). Conclusions. The prevalence of dMMRP tumors in this age group appears to be similar to international literature. dMMRP tumors tends to be associated with earlier stages and better outcomes compared to pMMRP cases. dMMRP can serve as a biomarker for better prognosis. These results are of value in directing the clinical management of young patients with CRC.

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