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Microsatellite instability and mutations in BRAF and KRAS are significant predictors of disseminated disease in colon cancer.

ABSTRACT: Molecular alterations are well studied in colon cancer, however there is still need for an improved understanding of their prognostic impact. This study aims to characterize colon cancer with regard to KRAS, BRAF, and PIK3CA mutations, microsatellite instability (MSI), and average DNA copy number, in connection with tumour dissemination and recurrence in patients with colon cancer.Disease stage II-IV colon cancer patients (n?=?121) were selected. KRAS, BRAF, and PIK3CA mutation status was assessed by pyrosequencing and MSI was determined by analysis of mononucleotide repeat markers. Genome-wide average DNA copy number and allelic imbalance was evaluated by SNP array analysis.Patients with mutated KRAS were more likely to experience disease dissemination (OR 2.75; 95% CI 1.28-6.04), whereas the opposite was observed for patients with BRAF mutation (OR 0.34; 95% 0.14-0.81) or MSI (OR 0.24; 95% 0.09-0.64). Also in the subset of patients with stage II-III disease, both MSI (OR 0.29; 95% 0.10-0.86) and BRAF mutation (OR 0.32; 95% 0.16-0.91) were related to lower risk of distant recurrence. However, average DNA copy number and PIK3CA mutations were not associated with disease dissemination.The present study revealed that tumour dissemination is less likely to occur in colon cancer patients with MSI and BRAF mutation, whereas the presence of a KRAS mutation increases the likelihood of disseminated disease.

SUBMITTER: Birgisson H

PROVIDER: S-EPMC4364587 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

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Microsatellite instability and mutations in BRAF and KRAS are significant predictors of disseminated disease in colon cancer.

Birgisson Helgi H Edlund Karolina K Wallin Ulrik U Påhlman Lars L Kultima Hanna Göransson HG Mayrhofer Markus M Micke Patrick P Isaksson Anders A Botling Johan J Glimelius Bengt B Sundström Magnus M

BMC cancer 20150314

<h4>Background</h4>Molecular alterations are well studied in colon cancer, however there is still need for an improved understanding of their prognostic impact. This study aims to characterize colon cancer with regard to KRAS, BRAF, and PIK3CA mutations, microsatellite instability (MSI), and average DNA copy number, in connection with tumour dissemination and recurrence in patients with colon cancer.<h4>Methods</h4>Disease stage II-IV colon cancer patients (n = 121) were selected. KRAS, BRAF, an ...[more]

PMID: 25884297

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Project description:BackgroundThe fact that the receptors for the TNF-related apoptosis inducing ligand (TRAIL) are almost invariably expressed in colorectal cancer (CRC) represents the rationale for the employment of TRAIL-receptors targeting compounds for the therapy of patients affected by this tumor. Yet, first reports on the use of these bioactive agents provided disappointing results. We therefore hypothesized that loss of membrane-bound TRAIL-R might be a feature of some CRC and that the evaluation of membrane staining rather than that of the overall expression of TRAIL-R might predict the response to TRAIL-R targeting compounds in this tumor.Aim and methodsThus, we evaluated the immunofluorescence pattern of TRAIL-receptors and E-cadherin to assess the fraction of membrane-bound TRAIL-receptors in 231 selected patients with early-stage CRC undergoing surgical treatment only. Moreover, we investigated whether membrane staining for TRAIL-receptors as well as the presence of KRAS mutations or of microsatellite instability (MSI) had an effect on survival and thus a prognostic effect.ResultsAs expected, almost all CRC samples stained positive for TRAIL-R1 and 2. Instead, membrane staining for these receptors was positive in only 71% and 16% of samples respectively. No correlation between KRAS mutation status or MSI-phenotype and prognosis could be detected. TRAIL-R1 staining intensity correlated with survival in univariate analysis, but only membranous staining of TRAIL-R1 and TRAIL-R2 on cell membranes was an independent predictor of survival (cox multivariate analysis: TRAIL-R1: p = 0.019, RR 2.06[1.12-3.77]; TRAIL-R2: p = 0.033, RR 3.63[1.11-11.84]).ConclusionsIn contrast to the current assumptions, loss of membrane staining for TRAIL-receptors is a common feature of early stage CRC which supersedes the prognostic significance of their staining intensity. Failure to achieve therapeutic effects in recent clinical trials using TRAIL-receptors targeting compounds might be due to insufficient selection of patients bearing tumors with membrane-bound TRAIL-receptors.

Project description:The prognostic value of BRAF and KRAS mutations within microsatellite-unstable (MSI) and microsatellite-stable (MSS) subgroups of resected colon carcinoma patients remains controversial. We examined this question in prospectively collected biospecimens from stage III colon cancer with separate analysis of MSI and MSS tumors from patients receiving adjuvant FOLFOX +/- cetuximab in two adjuvant therapy trials.Three groups were defined: BRAF Mutant, KRAS Mutant, and double wild-type. The analytic strategy involved estimation of study-specific effects, assessment of homogeneity of results, and then analysis of pooled data as no differences in patient outcome were found between treatment arms in both trials. Associations of mutations with patient outcome were analyzed, and multivariable models were adjusted for treatment and relevant factors.Four thousand four hundred eleven tumors were evaluable for BRAF and KRAS mutations and mismatch repair status; 3934 were MSS and 477 were MSI. In MSS patients, all BRAF V600E mutations (hazard ratio [HR] = 1.54, 95% confidence interval [CI] = 1.23 to 1.92, P < .001), KRAS codon 12 alterations, and p.G13D mutations (HR?=?1.60, 95% CI?=?1.40 to 1.83, P < .001) were associated with shorter time to recurrence (TTR) and shorter survival after relapse (SAR; HR?=?3.02 , 95% CI?=?2.32 to 3.93, P < .001, and HR?=?1.20, 95% CI?=?1.01 to 1.44, P = .04, respectively). Overall survival (OS) in MSS patients was poorer for BRAF-mutant patients (HR?=?2.01, 95% CI?=?1.56 to 2.57, P < .001) and KRAS-mutant patients (HR?=?1.62, 95% CI?=?1.38 to 1.91, P < .001) vs wild-type. No prognostic role of KRAS or BRAF mutations was seen in MSI patients. Furthermore, no interaction was found between treatment arm (with or without cetuximab) and KRAS and BRAF mutations for TTR or OS in MSS patients.In a pooled analysis of resected stage III colon cancer patients receiving adjuvant FOLFOX, BRAF or KRAS mutations are independently associated with shorter TTR, SAR, and OS in patients with MSS, but not MSI, tumors. Future clinical trials in the adjuvant setting should consider these mutations as important stratification factors.

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Microsatellite instability and mutations in BRAF and KRAS are significant predictors of disseminated disease in colon cancer.

Publications

Microsatellite instability and mutations in BRAF and KRAS are significant predictors of disseminated disease in colon cancer.

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