Project description:We showed that some microRNAs could be characteristic of the progression from adenoma to adenocarcinoma in colorectal cancer. 48 colorectal biopsy samples (28 adenomas, 15 adenocarcinomas and 5 normal mucosae) were analyzed. We generated three comparisons: adenomas versus. normal mucosae, adenocarcinomas versus. normal mucosae, and adenocarcinomas versus. adenomas.
Project description:We showed that a large number of genes were deregulated in colorectal adenomas in comparison with colorectal normal mucosae. 37 colorectal adenoma and 9 colorectal normal mucosa samples were analyzed. We generated a comparison between adenomas and normal mucosae.
Project description:Aberrant methylation of DNA is supposed to be a major and early driver of colonic adenoma development and may also lead to colorectal cancer (CRC) formation. While gene methylation assays are used already for CRC screening, differential epigenetic alterations of recurring and non-recurring colorectal adenomas have yet not been systematically investigated. Here, we collected a sample set (n=72) of formalin-fixed paraffin-embedded (FFPE) primary colorectal adenomas without recurrence (n=30), primary adenomas with recurrence at the same location (n=19), so-called “matched pair samples” (n=10; comprising the primary adenoma and the recurrent adenoma) and normal mucosa specimens (n=3). We aimed to unveil differentially methylated CpG positions (DMPs) across the methylome of the selected samples using the Illumina HumanMethylation 450K BeadChip array. Unsupervised hierarchical clustering exhibited a significant association of methylation patterns with the histological subtypes. No significant DMPs were identified comparing primary adenomas with and without recurrence. Despite that, a total of 5,094 DMPs (FDR<0.05, fold change>10%) were identified in the comparisons of recurrent adenomas vs. (non-) matched primary adenomas with recurrence (674; 98% hypermethylated), recurrent adenomas vs. primary adenomas with and without recurrence (241; 99% hypermethylated) and adenomas vs. normal mucosae (4,179; 46% hypermethylated). DMPs in CpG islands were frequently hypermethylated whereas open sea and shelves exhibited hypomethylation. Gene ontological analysis demonstrated enrichment of genes associated with the immune system, inflammatory processes, and cancer-pathways. We conclude that methylation data is helpful to contribute to a more stable and reproducible histological adenoma classification which is a prerequisite to establishing profound surveillance guidelines
Project description:We showed that a large number of genes were deregulated in colorectal adenocarcinomas in comparison with colorectal normal mucosae. 9 paired tumor-normal colorectal samples were analyzed. We generated a comparison between adenocarcinomas and normal mucosae.
Project description:Approximately two decades ago, Vogelstein and Fearon proposed the adenoma-carcinoma sequence of sporadic CRC development and illustrated the accumulation of genetic alterations during the stepwise progression, thereby providing a guideline for clinical practice. Although the detection and excision of precancerous lesions could prevent colorectal cancer and reduce mortality, 6% of adenomas will ultimately develop into colorectal cancer. Thus, this genetic model for colorectal tumorigenesis may not completely reflect the complex essence of the disease and whether the mode of initiation of the events in the multistep progression affects the outcome of CRC is still unknown. In this study, mRNA and miRNA expression profiling was performed with human colorectal tissues, including normal mucosa, adenoma and adenocarcinoma. Then, an integrated approach was adopted to establish the regulatory interaction networks that were correlated with colorectal carcinogenesis. Finally, a 55-gene signature whose expression was down-regulated in precancerous lesions compared to normal tissue was identified as a potential early indicator of CRC survival. The results suggested that genes related to immunity and homeostasis played a critical role in protection against adenoma initiation and that the altered molecular events that influence colorectal cancer prognosis may be set in an early, precancerous stage. Four types of human colorectal tissues were selected by colonoscopic resection or colorectal surgery, including 12 normal mucosae, 21 low-grade adenomas (mild or moderate atypical hyperplasia), 30 high-grade adenomas (severe atypical hyperplasia or carcinoma in situ) and 25 adenocarcinomas. Gene expression profiling analysis of these samples was performed using Agilent 4x44K human whole genome gene expression microarray (G4112F).
Project description:Approximately two decades ago, Vogelstein and Fearon proposed the adenoma-carcinoma sequence of sporadic CRC development and illustrated the accumulation of genetic alterations during the stepwise progression, thereby providing a guideline for clinical practice. Although the detection and excision of precancerous lesions could prevent colorectal cancer and reduce mortality, 6% of adenomas will ultimately develop into colorectal cancer. Thus, this genetic model for colorectal tumorigenesis may not completely reflect the complex essence of the disease and whether the mode of initiation of the events in the multistep progression affects the outcome of CRC is still unknown. In this study, mRNA and miRNA expression profiling was performed with human colorectal tissues, including normal mucosa, adenoma and adenocarcinoma. Then, an integrated approach was adopted to establish the regulatory interaction networks that were correlated with colorectal carcinogenesis. Finally, a 55-gene signature whose expression was down-regulated in precancerous lesions compared to normal tissue was identified as a potential early indicator of CRC survival. The results suggested that genes related to immunity and homeostasis played a critical role in protection against adenoma initiation and that the altered molecular events that influence colorectal cancer prognosis may be set in an early, precancerous stage. Four types of human colorectal tissues were selected by colonoscopic resection or colorectal surgery, including 15 normal mucosae, 39 low-grade adenomas (mild or moderate atypical hyperplasia), 20 high-grade adenomas (severe atypical hyperplasia or carcinoma in situ) and 33 adenocarcinomas. MicroRNA expression profiling analysis of these samples was performed on Agilent 8Ã16K Human miRNA Microarray V3 (G4470C).
Project description:We explored the differential methylation patterns found in cfDNA between healthy controls (individuals with no colorectal findings, NCF) and patients with advanced neoplasia (advanced adenomas and colorectal cancer, AA andCRC) using pooled samples, to determine if pooled serum cfDNA samples can be used to search for non-invasive methylation biomarkers, as an affordable and efficient alternative to tissue biopsy. cfDNA was extracted from serum samples and methylation measurements were assessed with the Infinium MethylationEPIC BeadChip. Data was mainly preprocessed and analyzed with R/Bioconductor packages.