Dataset Information

Sensitive detection of colorectal cancer in peripheral blood by septin 9 DNA methylation assay.

ABSTRACT:

Background

Colorectal cancer (CRC) is the second leading cause of cancer deaths despite the fact that detection of this cancer in early stages results in over 90% survival rate. Currently less than 45% of at-risk individuals in the US are screened regularly, exposing a need for better screening tests. We performed two case-control studies to validate a blood-based test that identifies methylated DNA in plasma from all stages of CRC.

Methodology/principal findings

Using a PCR assay for analysis of Septin 9 (SEPT9) hypermethylation in DNA extracted from plasma, clinical performance was optimized on 354 samples (252 CRC, 102 controls) and validated in a blinded, independent study of 309 samples (126 CRC, 183 controls). 168 polyps and 411 additional disease controls were also evaluated. Based on the training study SEPT9-based classification detected 120/252 CRCs (48%) and 7/102 controls (7%). In the test study 73/126 CRCs (58%) and 18/183 control samples (10%) were positive for SEPT9 validating the training set results. Inclusion of an additional measurement replicate increased the sensitivity of the assay in the testing set to 72% (90/125 CRCs detected) while maintaining 90% specificity (19/183 for controls). Positive rates for plasmas from the other cancers (11/96) and non-cancerous conditions (41/315) were low. The rate of polyp detection (>1 cm) was approximately 20%.

Conclusions/significance

Analysis of SEPT9 DNA methylation in plasma represents a straightforward, minimally invasive method to detect all stages of CRC with potential to satisfy unmet needs for increased compliance in the screening population. Further clinical testing is warranted.

SUBMITTER: Grutzmann R

PROVIDER: S-EPMC2582436 | biostudies-literature | 2008

REPOSITORIES: biostudies-literature

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Publications

Sensitive detection of colorectal cancer in peripheral blood by septin 9 DNA methylation assay.

Grützmann Robert R Molnar Bela B Pilarsky Christian C Habermann Jens K JK Schlag Peter M PM Saeger Hans D HD Miehlke Stephan S Stolz Thomas T Model Fabian F Roblick Uwe J UJ Bruch Hans-Peter HP Koch Rainer R Liebenberg Volker V Devos Theo T Song Xiaoling X Day Robert H RH Sledziewski Andrew Z AZ Lofton-Day Catherine C

PloS one 20081119 11

<h4>Background</h4>Colorectal cancer (CRC) is the second leading cause of cancer deaths despite the fact that detection of this cancer in early stages results in over 90% survival rate. Currently less than 45% of at-risk individuals in the US are screened regularly, exposing a need for better screening tests. We performed two case-control studies to validate a blood-based test that identifies methylated DNA in plasma from all stages of CRC.<h4>Methodology/principal findings</h4>Using a PCR assay ...[more]

PMID: 19018278

Similar Datasets

Project description:BackgroundThe septin 9 gene (SEPT9) codes for a GTP-binding protein associated with filamentous structures and cytoskeleton formation. SEPT9 plays a role in multiple cancers as either an oncogene or a tumor suppressor gene. Regulation of SEPT9 expression is complex and not well understood; however, hypermethylation of the gene was recently introduced as a biomarker for early detection of colorectal cancer (CRC) and has been linked to cancer of the breast and of the head and neck. Because the DNA methylation landscape of different regions of SEPT9 is poorly understood in cancer, we analyzed the methylation patterns of this gene in distinct cell populations from normal and diseased colon mucosa.MethodsLaser capture microdissection was performed to obtain homogeneous populations of epithelial and stromal cells from normal, adenomatous, and tumorous colon mucosa. Microdissected samples were analyzed using direct bisulfite sequencing to determine the DNA methylation status of eight regions within and near the SEPT9 gene. Septin-9 protein expression was assessed using immunohistochemistry (IHC).ResultsRegions analyzed in SEPT9 were unmethylated in normal tissue except for a methylation boundary detected downstream of the largest CpG island. In adenoma and tumor tissues, epithelial cells displayed markedly increased DNA methylation levels (>80%, p <0.0001) in only one of the CpG islands investigated. SEPT9 methylation in stromal cells increased in adenomatous and tumor tissues (?50%, p <0.0001); however, methylation did not increase in stromal cells of normal tissue close to the tumor. IHC data indicated a significant decrease (p <0.01) in Septin-9 protein levels in epithelial cells derived from adenoma and tumor tissues; Septin-9 protein levels in stromal cells were low in all tissues.ConclusionsHypermethylation of SEPT9 in adenoma and CRC specimens is confined to one of several CpG islands of this gene. Tumor-associated aberrant methylation originates in epithelial cells; stromal cells appear to acquire hypermethylation subsequent to epithelial cells, possibly through field effects. The region in SEPT9 with disease-related hypermethylation also contains the CpGs targeted by a novel blood-based screening test (Epi proColon®), providing further support for the clinical relevance of this biomarker.

Dataset Information

Sensitive detection of colorectal cancer in peripheral blood by septin 9 DNA methylation assay.

Background

Methodology/principal findings

Conclusions/significance

Publications

Sensitive detection of colorectal cancer in peripheral blood by septin 9 DNA methylation assay.

Similar Datasets

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