Project description:DNA methylation in colorectal cancer diagnosis. The Illumina GoldenGate Methylation Cancer Panel I was used to select a set of candidates markers informative of colorectal cancer diagnosis from 807 cancer-related genes. In the discovery phase, tumor tissue and paired adjacent normal mucosa from 92 colorectal patients were analyzed.
Project description:Unearthing of silenced genes in colorectal cancer (CRC) is of great importance. We employed oligonucleotide microarray to find changes in global gene expression of five CRC cell lines. These were analyzed before and after treatment with the 5-aza-2'-Deoxycitidine. Expression of the responding genes was integrated with gene expression profiling generated by microarray analysis of matched colorectal tissue samples. Selected candidates were subjected to methylation-specific PCR (MSP) and real-time quantitative reverse transcription-PCR using CRC cell lines and paired tumor and normal samples from CRC patients. Sixty eight genes were re-expressed after 5-aza-2'-Deoxycitidine treatment and over-expressed in normal colorectal mucosa, including genes that were known to be methylated in CRC. After applying study selection criteria, we identified 16 potential genes. Two candidates were selected (ASPP1 and SCARA5). Among 15 CRC cell lines, methylation was identified in SCARA5 (20%). The methylation status of SCARA5 was subsequently investigated in 23 paired colorectal tissue samples; methylation was detected in 17%, respectively. Observed promoter methylation showed a tendency towards methylation in tumor-derived samples, in SCARA5 gene. Significant down expression of SCARA5 mRNA was observed in CRC cell lines and tumor tissues compared to adjacent normal tissues (P < 0.001 and P = 0.001, respectively). The use of genome-wide screening led to the identification of a group of candidate genes. Among them, SCARA5 was methylated and markedly down-regulated in CRC. SCARA5 gene may have a role in CRC tumorigenesis.
Project description:In this work, we performed gene expression profiling for twenty-paired blood samples collected from healthy controls before and after colonoscopy, and twenty blood samples collected from<br>colorectal cancer patients after colonoscopy. The aim of this study is to determine how significant the colonoscopy procedure may impact the global gene expression in human peripheral blood, and whether this colonoscopy induced variability would bias the biomarker research for colorectal cancer early detection.
Project description:We investigate the relevance of RNA integrity in gene expression analysis as well as analysis methods to accommodate the possible effects of degradation using paired tumour and normal samples from colorectal cancer patients undergoing colonic resection.
Project description:The purpose of this study is to identify miRNAs involved in the pathology of colorectal cancer (CRC) liver metastasis and investigate their underlying mechanisms. A total of 39 miRNAs were identified to be differentially expressed between 16 primary CRC tissues with liver metastases and 16 CRC tissues without liver metastases from 32 patients by Affymetric miRNA microarrays. 16 coloretcal cancer tissues with liver metastasis and 16 colorectal cancer tissues without liver metastasis were included in this study for RNA extraction and hybridization on Affymetrix microarrays. We sought to identify the differentially expressed miRNAs between colorectal cancer tissues with and without liver metastasis.
Project description:5 colorectal cancer (CRC) tissues and 5 paired non-tumor tissues from CRC patients were indirectly compared using a 17K cDNA microarray.
Project description:DNA methylation in colorectal cancer diagnosis. The Illumina GoldenGate Methylation Cancer Panel I was used to select a set of candidates markers informative of colorectal cancer diagnosis from 807 cancer-related genes. In the discovery phase, tumor tissue and paired adjacent normal mucosa from 92 colorectal patients were analyzed. Bisulphite converted DNA from 92 colorectal tumor samples and paired adjacent normal mucosa were hybridised to the Illumina GoldenGate Methylation Cancer Panel I. Additionally, replicates were hybridised for five tumor tissue and their corresponding normal mucosa for reproducibility purposes, totalling 194 samples. Three samples (SAMPLEs 49, 51, and 162) and 50 loci did not reach the quality criteria required regarding the signal-to-noise ratio and were therefore excluded from further analysis. One additional non-tumoral sample (SAMPLE 15) was removed because it exhibited a methylation pattern quiet different from that shown by the rest of normal specimens, which could be indicative of hybridization errors. These Samples and loci are included in the raw data matrix to allow other investigators to use them if different criteria are applied. They have been also included in the Sample tables with missing values in order to preserve the structure of the data across records/files (See 'data processing' section for more details).
