C groups. The nearest shrunken centroid method (Prediction Analysis for miroarrays ?PAM) was applied for sample classification from gene expression data. The pre-processing, data mining and statistical steps were performed using R-environment with Bioconductor libraries. Hierarchical cluster analysis represents on each comparisons of correlation. Logistic regression was applied to analyze dependence of binary diagnostic variables (represented 0 as control, 1 as disease). Discriminant and principal component analysis were also performed. In the discriminant analysis, leave-one out classification was applied for crossvalidation.Materials and Methods Patients and samplesAfter informed consent of untreated patients, colon biopsy samples were taken during endoscopic CB-5083 intervention and stored in RNALater Reagent (Qiagen Inc, Germantown, US) at ?0uC. Altogether 147 biopsy specimen (53/original set/and additionally 94 fresh frozen/independent set/samples) were analyzed in our study. Total RNA was extracted and Affymetrix microarray analysis was performed on biopsies of patients with tubulovillous/ villous adenomas (n = 29, 13 high-grade dysplastic and 16 with low-grade dysplasia), colorectal adenocarcinoma (n = 27, 14 early and 13 advanced CRC) and of healthy normal controls (n = 38). Fifty three microarrays (11 normal, 
20 adenoma, 22 CRC) had been hybridized earlier (original samples set), their data files were used in a previous studies using different comparisons [12?4] and are available in the Gene Expession Omnibus database (series accession numbers: GSE4183 and GSE10714), while GSE37364 accession number refers to the data files of newly hybridized 94 microarrays (independent sample set). The diagnostic groups and the number of patients in each group are represented in Table 1. Detailed patient specification is described in Table S1. The study involves human subjects. Therefore the study was approved by the Regional and Institutional Committee of Science and Research Ethics (TUKEB Nr.: 69/2008. Semmelweis University Regional and Institutional Committee of Science and Research Ethics, Budapest, Hungary). Written informed consent was obtained from all patients.Array real-time PCRCommercially available real-time PCR assays were applied for expression measuring of 11 discriminatory transcripts (www.rocheapplied-science.com). The list of the real-time ready assays can be seen in the Table 2. Gene specific forward and reverse primers and fluorescently labeled hydrolysis probes from Universal ProbeLibrary (F. Hoffmann-La Roche Ltd., Switzerland, Basel) were lyophilized into wells of 384-well PCR plates. Using MK 8931 custom synthesis Transcriptor First Strand cDNA Synthesis Kit (Roche), 2.5 mg total RNA from 20 healthy, 24 adenoma, 24 CRC biopsy samples were reverse transcribed (Table 1). The quality of the cDNA samples was checked by real-time PCR for SDHA (succinate dehydrogenase complex, subunit A, flavoprotein) housekeeping gene. The expression analysis of the selected genes was performed from 5 ng/sample cDNA template, using the newly designed array realtime PCR cards and LightCycler 480 Probes Master (Roche). The measurements were performed using a LightCycler 480 instrument as described in the products User Guide (http://www.rocheapplied-science.com). After enzyme activation and denaturation at 95uC for 10 min, 45 PCR cycles were performed (denaturation at 95uC for 10 sec, annealing and extension at 60uC for 30 sec and signal detection at 72uC for 1 sec). In order t.C groups. The nearest shrunken centroid method (Prediction Analysis for miroarrays ?PAM) was applied for sample classification from gene expression data. The pre-processing, data mining and statistical steps were performed using R-environment with Bioconductor libraries. Hierarchical cluster analysis represents on each comparisons of correlation. Logistic regression was applied to analyze dependence of binary diagnostic variables (represented 0 as control, 1 as disease). Discriminant and principal component analysis were also performed. In the discriminant analysis, leave-one out classification was applied for crossvalidation.Materials and Methods Patients and samplesAfter informed consent of untreated patients, colon biopsy samples were taken during endoscopic intervention and stored in RNALater Reagent (Qiagen Inc, Germantown, US) at ?0uC. Altogether 147 biopsy specimen (53/original set/and additionally 94 fresh frozen/independent set/samples) were analyzed in our study. Total RNA was extracted and Affymetrix microarray analysis was performed on biopsies of patients with tubulovillous/ villous adenomas (n = 29, 13 high-grade dysplastic and 16 with low-grade dysplasia), colorectal adenocarcinoma (n = 27, 14 early and 13 advanced CRC) and of healthy normal controls (n = 38). Fifty three microarrays (11 normal, 20 adenoma, 22 CRC) had been hybridized earlier (original samples set), their data files were used in a previous studies using different comparisons [12?4] and are available in the Gene Expession Omnibus database (series accession numbers: GSE4183 and GSE10714), while GSE37364 accession number refers to the data files of newly hybridized 94 microarrays (independent sample set). The diagnostic groups and the number of patients in each group are represented in Table 1. Detailed patient specification is described in Table S1. The study involves human subjects. Therefore the study was approved by the Regional and Institutional Committee of Science and Research Ethics (TUKEB Nr.: 69/2008. Semmelweis University Regional and Institutional Committee of Science and Research Ethics, Budapest, Hungary). Written informed consent was obtained from all patients.Array real-time PCRCommercially available 
real-time PCR assays were applied for expression measuring of 11 discriminatory transcripts (www.rocheapplied-science.com). The list of the real-time ready assays can be seen in the Table 2. Gene specific forward and reverse primers and fluorescently labeled hydrolysis probes from Universal ProbeLibrary (F. Hoffmann-La Roche Ltd., Switzerland, Basel) were lyophilized into wells of 384-well PCR plates. Using Transcriptor First Strand cDNA Synthesis Kit (Roche), 2.5 mg total RNA from 20 healthy, 24 adenoma, 24 CRC biopsy samples were reverse transcribed (Table 1). The quality of the cDNA samples was checked by real-time PCR for SDHA (succinate dehydrogenase complex, subunit A, flavoprotein) housekeeping gene. The expression analysis of the selected genes was performed from 5 ng/sample cDNA template, using the newly designed array realtime PCR cards and LightCycler 480 Probes Master (Roche). The measurements were performed using a LightCycler 480 instrument as described in the products User Guide (http://www.rocheapplied-science.com). After enzyme activation and denaturation at 95uC for 10 min, 45 PCR cycles were performed (denaturation at 95uC for 10 sec, annealing and extension at 60uC for 30 sec and signal detection at 72uC for 1 sec). In order t.
