Background & Aims-5-FU-based adjuvant chemotherapy does not increase survival times of patients with colorectal tumors with microsatellite instability. We determined the response of patients with colorectal tumors with the CpG island methylator phenotype (CIMP) to 5-FU-based therapy.

BackgroundLynch syndrome (LS) is a hereditary condition that increases the risk for endometrial and other cancers. The identification of endometrial cancer (EC) patients with LS has the potential to influence life-saving interventions. We aimed to study the prevalence of LS among EC patients in our population.MethodsUniversal screening for LS was applied for a consecutive series EC. Tumor testing using microsatellite instability (MSI), immunohistochemistry (IHC) for mismatch-repair (MMR) protein expression and MLH1-methylation analysis, when required, was used to select LS-suspicious cases. Sequencing of corresponding MMR genes was performed.ResultsOne hundred and seventy-three EC (average age, 63 years) were screened. Sixty-one patients (35%) had abnormal IHC or MSI results. After MLH1 methylation analysis, 27 cases were considered suspicious of LS. From these, 22 were contacted and referred for genetic counseling. Nineteen pursued genetic testing and eight were diagnosed of LS. Mutations were more frequent in younger patients (<50 yrs). Three cases had either intact IHC or MSS and reinforce the need of implement the EC screening with both techniques.ConclusionThe prevalence of LS among EC patients was 4.6% (8/173); with a predictive frequency of 6.6% in the Spanish population. Universal screening of EC for LS is recommended.

Inactivation of MLH1 due to promoter hypermethylation strongly suggests a sporadic origin , providing exclusion criteria for Lynch syndrome. The aim of this study is to compare the utility of methylation analysis of MLH1 and BRAF V600E mutations for the selection of patients with MLH1 negative colorectal cancer for genetic testing. MLH1 methylation status was evaluated by MethyLight and methylation-specific MLPA (MS-MLPA) in tumor DNA from 73 colorectal cancer patients with loss of MLH1 protein expression. These tumors were analyzed for BRAF V600E mutations , and genetic testing for germline MLH1 mutations was performed in all corresponding patients. Ten patients had germline mutations in MLH1 and none of their tumors showed significant MLH1 methylation or BRAF V600E mutation. MLH1 genetic testing excluded patients by MethyLight in 47 patients (64%) , by MS-MLPA in 49 (67%) , and BRAF V600E mutation in only 25 patients (34%) ( 2 P ‫؍‬ 0.00001). Specificity was 75% for MethyLight , 78% for MS-MLPA and 40% for BRAF V600E mutation. The use of MethyLight or MS-MLPA instead of BRAF mutation resulted in a cost reduction of 41% and 45% , respectively , per every MLH1 mutation detected. Taken together , methylation analysis of MLH1 shows better performance characteristics than BRAF V600E mutation in the selection of patients for genetic testing of MLH1 , especially when using

Background and AimAberrant hypermethylation of cancer-related genes has emerged as a promising strategy for the development of diagnostic, prognostic and predictive biomarkers in human cancer, including colorectal cancer (CRC). The aim of this study was to perform a systematic and comprehensive analysis of a panel of CRC-specific genes as potential diagnostic, prognostic and predictive biomarkers in a large, population-based CRC cohort.Patients and MethodsMethylation status of the SEPT9, TWIST1, IGFBP3, GAS7, ALX4 and miR137 genes was studied by quantitative bisulfite pyrosequencing in a population-based cohort of 425 CRC patients.ResultsMethylation levels of all genes analyzed were significantly higher in tumor tissues compared to normal mucosa (p<0.0001); however, cancer-associated hypermethylation was most frequently observed for miR137 (86.7%) and IGFBP3 (83%) in CRC patients. Methylation analysis using the combination of these two genes demonstrated greatest accuracy for the identification of colonic tumors (sensitivity 95.5%; specificity 90.5%). Low levels of IGFBP3 promoter methylation emerged as an independent risk factor for predicting poor disease free survival in stage II and III CRC patients (HR = 0.49, 95% CI: 0.28–0.85, p = 0.01). Our results also suggest that stage II & III CRC patients with high levels of IGFBP3 methylation do not benefit from adjuvant 5FU-based chemotherapy.ConclusionBy analyzing a large, population-based CRC cohort, we demonstrate the potential clinical significance of miR137 and IGFBP3 hypermethylation as promising diagnostic biomarkers in CRC. Our data also revealed that IGFBP3 hypermethylation may serve as an independent prognostic and predictive biomarker in stage II and III CRC patients.

Background: Epidemiological data on Creutzfeldt-Jakob disease (CJD) from Latin America are limited. We present a comprehensive epidemiological survey on CJD patients in Argentina based on systematic surveillance between 1997 and 2008. Methods: A CJD Surveillance Referral Center (SRC) was established in Argentina in 1997; previously a Neuropathology Referral Center was used from 1983 to 1996. All suspected cases referred to the SRC were classified using established criteria on the basis of information derived from the following: clinical data form, EEG, MRI (both for central review), cerebrospinal fluid (CSF) for protein 14-3-3 Western blot (WB), autopsy or biopsy material for neuropathology, prion protein (PrP) immunohistochemistry and PrP WB, as well as blood for DNA studies (when brain tissue was not available). Results: Of the 517 patients referred to the SRC between 1997 and 2008, 211 (40.8%) had CJD or other transmissible spongiform encephalopathies (TSEs) (definite or probable). Possible cases totaled 14.5%, while cases with no WHO criteria accounted for 16.4%. Non-CJD cases excluded by biopsy/autopsy or during follow-up corresponded to 28.2% of the 517 referrals. Main differential diagnoses included neurodegenerative diseases such as Alzheimer’s disease, frontotemporal dementia, vascular, metabolic or viral encephalopathy, and Hashimoto’s disease. Five percent of referred patients ultimately recovered. Eighty-three percent of TSE cases were sporadic CJD; 17% were genetic, mainly E200K (15.6%); the remaining 1.4% included an octarepeat insertion and two Gerstmann-Sträussler-Scheinker cases (P102L). Seventy-four of 100 definite cases had frozen tissue available for molecular subtyping (PrP^Sc/codon 129). CSF protein 14-3-3 WB sensitivity was 72.3% and specificity was 92.1%. Clinical diagnostic criteria for probable CJD when compared to definite diagnosis by neuropathology showed 71.3% sensitivity, 86.2% specificity, 94.4% positive predictive value and 48% negative predictive value. Country incidence increased over time and reached 0.85 cases per million in 2008, with the highest rate detected in the city of Buenos Aires (1.8). Districts with 6% of the total population have never reported suspected cases. Conclusion: In spite of an increase in incidence observed over time, the difference between Buenos Aires city, where the incidence is comparable to that of smaller European countries with higher population density, and the incidence observed in the rest of the country suggests underreporting in nonmetropolitan areas, probably due to a lack of access to specialized medical facilities. CSF WB sensitivity results for protein 14-3-3 were probably linked to the fact that testing was not routinely repeated during the course of the disease, when earlier test results had been negative. The spectrum of molecular CJD subtypes observed did not differ from other countries in Europe. No iatrogenic or variant CJD cases were identified. The sensitivity and negative predictive value of clinical diagnostic criteria...