Improved Detection and Identification of Microsatellite Instability Features in Colorectal Cancer
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PROVIDER: PRJNA575920 | ENA |
REPOSITORIES: ENA
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Project description:Improved Detection and Identification of Microsatellite Instability Features in Colorectal Cancer
| PRJNA575921 | ENA
Project description:Background. Colorectal cancer develops through two main genetic instability pathways characterized by distinct pathologic features and clinical outcome. Results. We investigated colon cancer samples (23 characterized by microsatellite stability, MSS, and 16 by high microsatellite instability, MSI-H) for genome-wide expression of microRNA (miRNA) and mRNA. Based on combined miRNA and mRNA gene expression, a molecular signature consisting of twenty seven differentially expressed genes, inclusive of 8 miRNAs, could correctly distinguish MSI-H versus MSS colon cancer samples. Among the differentially expressed miRNAs, various members of the oncogenic miR-17-92 family were significantly up-regulated in MSS cancers. The majority of protein coding genes were also up-regulated in MSS cancers. Their functional classification revealed that they were most frequently associated with cell cycle, DNA replication, recombination, repair, gastrointestinal disease and immune response. Conclusions. This is the first report that indicates the existence of differences in miRNA expression between MSS versus MSI-H colorectal cancers. In addition, the work suggests that the combination of mRNA/miRNA expression signatures may represent a general approach for improving bio-molecular classification of human cancer.
2007-09-07 | E-TABM-326 | biostudies-arrayexpress
Project description:Analysis of microRNA expression of tumoral and non-tumoral colonic tissues. The aim of this study was to analyze the global miRNA signatures in various groups of well-characterized CRCs based on the presence of microsatellite instability (MSI).
2011-11-22 | GSE30454 | GEO
Project description:Analysis of microRNA expression of tumoral and non-tumoral colonic tissues. The aim of this study was to analyze the global miRNA signatures in various groups of well-characterized CRCs based on the presence of microsatellite instability (MSI). Total RNA from formalin-fixed paraffin-embedded tissue blocks from 4 different groups (normal colonic mucosa, Lynch syndrome tumors, sporadic MSI tumors and MSS tumors) was isolated using the RecoverAll Total Nucleic Acid Isolation Kit (Ambion) according to manufacturer instructions. MiRNA expression profiles were analyzed using miRNA microarray platform.
2011-11-22 | E-GEOD-30454 | biostudies-arrayexpress
Project description:In this study, we aimed to identify the different histopathological features of tumors with microsatellite instability (MSI) compared to microsatellite stable (MSS) in patients who underwent surgery for colorectal cancer. We also planned to determine how MSI affects prognostic parameters.
| 2398714 | ecrin-mdr-crc
Project description:Microsatellite instability (MSI) occurs in over 90% of Lynch syndrome cancers and is considered a hallmark of the disease. MSI is an early event in colon tumor development, but screening polyps for MSI remains controversial because of reduced sensitivity compared to more advanced neoplasms. To increase sensitivity, we investigated the use of a novel type of marker consisting of long mononucleotide repeat (LMR) tracts. Adenomas from 160 patients, ranging in age from 29-55 years old, were screened for MSI using the new markers and compared with current marker panels and immunohistochemistry standards. Overall, 15 tumors were scored as MSI-High using the LMRs compared to 9 for the NCI panel and 8 for the MSI Analysis System (Promega). This difference represents at least a 1.7-fold increase in detection of MSI-High lesions over currently available markers. Moreover, the number of MSI-positive markers per sample and the size of allelic changes were significantly greater with the LMRs (p = 0.001), which increased confidence in MSI classification. The overall sensitivity and specificity of the LMR panel for detection of mismatch repair deficient lesions were 100% and 96%, respectively. In comparison, the sensitivity and specificity of the MSI Analysis System were 67% and 100%; and for the NCI panel, 75% and 97%. The difference in sensitivity between the LMR panel and the other panels was statistically significant (p<0.001). The increased sensitivity for detection of MSI-High phenotype in early colorectal lesions with the new LMR markers indicates that MSI screening for the early detection of Lynch syndrome might be feasible.
| S-EPMC4529134 | biostudies-literature
Project description:Immunopeptidomic analyses of colorectal cancers with and without microsatellite instability
| PRJNA802838 | ENA
Project description:Inflammatory conditions caused by obstruction or perforation are common complications in colorectal cancer (CRC) and play important roles in tumor progression and immunosuppression. However, the significance of inflammatory conditions in the tumor response to immune checkpoint inhibitors (ICIs) remains unclear. We found a high microsatellite instability (MSI-H) CRC patient (Patient 1) whose primary tumor progressed and liver metastasis regressed during PD-1 blockade after having inflammatory conditions. Then, in 73 MSI-H CRCs, inflammatory conditions during ICI treatment were correlated with a poor tumor response, and an elevated NLR was associated with a poor immune status and resistance to ICIs. An organoid-T cell coculture model demonstrated an inhibited local immune response to treatment instead of systemic immunosuppression in Patient 1. Single-cell RNA sequencing suggested that neutrophils suppress the immune microenvironment mostly through CTLA-4-associated pathways. Therefore, inflammatory conditions in MSI-H CRCs correlate with resistance to ICIs through neutrophil-associated immunosuppression. Additional CTLA-4 blockade may improve the sensitivity to PD-1 blockade.
2021-07-09 | GSE179784 | GEO
Project description:Colorectal cancer is the second leading cause of cancer death worldwide, and the incidence of this disease is expected to increase as global socioeconomic changes occur. Immune checkpoint inhibition therapy is effective in treating a minority of colorectal cancer tumors; however, microsatellite stable tumors do not respond well to this treatment. Emerging cancer immunotherapeutic strategies aim to activate a cytotoxic T cell response against tumor-specific antigens, presented exclusively at the cell surface of cancer cells. These antigens are rare and are most effectively identified with a mass spectrometry-based approach, which allows the direct sampling and sequencing of these peptides. While the few tumor-specific antigens identified to date are derived from coding regions of the genome, recent findings indicate that a large proportion of tumor-specific antigens originate from allegedly noncoding regions. Here, we employed a novel proteogenomic approach to identify tumor antigens in a collection of colorectal cancer-derived cell lines and biopsy samples consisting of matched tumor and normal adjacent tissue. The generation of personalized cancer databases paired with mass spectrometry analyses permitted the identification of more than 30 000 unique MHC I-associated peptides. We identified 19 tumor-specific antigens in both microsatellite stable and unstable tumors, over two-thirds of which were derived from non-coding regions. Many of these peptides were derived from source genes known to be involved in colorectal cancer progression, suggesting that antigens from these genes could have therapeutic potential in a wide range of tumors. These findings could benefit the development of T cell-based vaccines, in which T cells are primed against these antigens to target and eradicate tumors. Such a vaccine could be used in tandem with existing immune checkpoint inhibition therapies, to bridge the gap in treatment efficacy across subtypes of colorectal cancer with varying prognoses. Data are available via ProteomeXchange with identifier PXD028309.
2022-05-01 | GSE195985 | GEO
Project description:A large proportion of indigenous African (IA) colorectal cancer (CRC) patients in South Africa are young (<50years), with no unique histopathological or molecular characteristics. Anatomical site as well as microsatellite instability (MSI) status have shown to be associated with different clinicopathological and molecular features. This study aimed to ascertain key histopathological and miRNA expression patterns in microsatellite stable (MSS) and low-frequency MSI (MSI-L) patients, to provide insight into the mechanism of the disease. This study revealed distinct histopathological features for Left Colon Cancer (LCC), and suggests BAT25/26, miRNAs let-7a-5p and miRNA-125a/b-5p as negative prognostic markers in African CRC patients.
2023-12-31 | GSE197088 | GEO