Identification and Validation of a Potential Marker of Tissue Quality Using Gene Expression Analysis of Human Colorectal Tissue.
Bottom Line: Results revealed that post-operative ischemia significantly alters gene expression in normal and CRC tissue samples.Both microarray analysis and qPCR revealed regulator of G-protein signaling 1 (RGS1) as a potential marker of CRC tissue quality and eukaryotic translation elongation factor 1 alpha 1 (EEF1A1) as a potential reference gene of post-operative tissue quality.Larger studies with additional time points and endpoints will be needed to confirm these results.
Affiliation: Indivumed GmbH, Hamburg, Germany.
Correlative studies have identified numerous biomarkers that are individualizing therapy across many medical specialties, including oncology. Accurate interpretation of these studies requires the collection of tissue samples of sufficient quality. Tissue quality can be measured by changes in levels of gene expression and can be influenced by many factors including pre-analytical conditions, ischemic effects and the surgical collection procedure itself. However, as yet there are no reliable biomarkers of tissue quality at researchers' disposal. The aim of the current study was to identify genes with expression patterns that fluctuated reproducibly in response to typical post-surgical stress (ischemia) in order to identify a specific marker of tissue quality. All tissue samples were obtained from patients with primary colorectal carcinoma (CRC) (N = 40) either via colonoscopy prior to surgery, or by surgical resection. Surgically resected tissue samples were divided into three groups and subjected to cold ischemia for 10, 20 or 45 minutes. Normal colorectal tissue and CRC tissue was analyzed using microarray and quantitative real-time PCR (qPCR). Comparing changes in gene expression between pre- and post-surgical tissue using microarray analysis identified a list of potential tissue quality biomarkers and this list was validated using qPCR. Results revealed that post-operative ischemia significantly alters gene expression in normal and CRC tissue samples. Both microarray analysis and qPCR revealed regulator of G-protein signaling 1 (RGS1) as a potential marker of CRC tissue quality and eukaryotic translation elongation factor 1 alpha 1 (EEF1A1) as a potential reference gene of post-operative tissue quality. Larger studies with additional time points and endpoints will be needed to confirm these results.
No MeSH data available.
Related in: MedlinePlus
Mentions: To investigate the expression of RGS1 and EEF1A1 in more detail, fold-changes in gene expression in ischemic tissue samples were assessed, and 2-fold changes indicated (Fig 3). RGS1 expression increased more than 2-fold in nearly all normal tissue samples (N10: 17/20 patients; N20: 19/20; N45: 19/20) as well as in the majority of tumor tissue samples (T10: 12/20; T20: 15/19; T45: 14/20). In normal tissue samples, RGS1 expression was at its highest within 10 minutes post-resection and expression appeared constant across all ischemia time points (Fig 3A). In tumor tissue samples, RGS1 expression level increased over time and was stable 20 minutes post-resection (Fig 3B). Time-dependent regulation of EEF1A1 in normal and tumor tissue resulted in stable expression (≤2-fold change) of EEF1A1 in nearly all samples (Fig 3C and 3D; N10: 17/20; N20: 18/20; N45: 19/20; T10: 18/20; T20: 17/20; T45: 13/20). However, the distribution of individual values within each group revealed a more focused clustering in response to resection in normal compared with tumor tissue samples.
No MeSH data available.