Microsatellite Instability in Colorectal Cancers: Carcinogenesis, Neo-Antigens, Immuno-Resistance and Emerging Therapies
A defect in the DNA repair system through a deficient mismatch repair system (dMMR) leads to microsatellite instability (MSI). Microsatellites are located in both coding and non-coding sequences and dMMR/MSI tumors are associated with a high mutation burden. Some of these mutations occur in coding s...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-06-01
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| Series: | Cancers |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2072-6694/13/12/3063 |
| _version_ | 1797529534836244480 |
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| author | Violaine Randrian Camille Evrard David Tougeron |
| author_facet | Violaine Randrian Camille Evrard David Tougeron |
| author_sort | Violaine Randrian |
| collection | DOAJ |
| description | A defect in the DNA repair system through a deficient mismatch repair system (dMMR) leads to microsatellite instability (MSI). Microsatellites are located in both coding and non-coding sequences and dMMR/MSI tumors are associated with a high mutation burden. Some of these mutations occur in coding sequences and lead to the production of neo-antigens able to trigger an anti-tumoral immune response. This explains why non-metastatic MSI tumors are associated with high immune infiltrates and good prognosis. Metastatic MSI tumors result from tumor escape to the immune system and are associated with poor prognosis and chemoresistance. Consequently, immune checkpoint inhibitors (ICI) are highly effective and have recently been approved in dMMR/MSI metastatic colorectal cancers (mCRC). Nevertheless, some patients with dMMR/MSI mCRC have primary or secondary resistance to ICI. This review details carcinogenesis and the mechanisms through which MSI can activate the immune system. After which, we discuss mechanistic hypotheses in an attempt to explain primary and secondary resistances to ICI and emerging strategies being developed to overcome this phenomenon by targeting other immune checkpoints or through vaccination and modification of microbiota. |
| first_indexed | 2024-03-10T10:15:13Z |
| format | Article |
| id | doaj.art-08a666dbc3244b22b1209627bbb7d869 |
| institution | Directory Open Access Journal |
| issn | 2072-6694 |
| language | English |
| last_indexed | 2024-03-10T10:15:13Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Cancers |
| spelling | doaj.art-08a666dbc3244b22b1209627bbb7d8692023-11-22T00:51:53ZengMDPI AGCancers2072-66942021-06-011312306310.3390/cancers13123063Microsatellite Instability in Colorectal Cancers: Carcinogenesis, Neo-Antigens, Immuno-Resistance and Emerging TherapiesViolaine Randrian0Camille Evrard1David Tougeron2Gastroenterology and Hepatology Department, Poitiers University Hospital, 86000 Poitiers, FranceMedical Oncology Department, Poitiers University Hospital, 86000 Poitiers, FranceGastroenterology and Hepatology Department, Poitiers University Hospital, 86000 Poitiers, FranceA defect in the DNA repair system through a deficient mismatch repair system (dMMR) leads to microsatellite instability (MSI). Microsatellites are located in both coding and non-coding sequences and dMMR/MSI tumors are associated with a high mutation burden. Some of these mutations occur in coding sequences and lead to the production of neo-antigens able to trigger an anti-tumoral immune response. This explains why non-metastatic MSI tumors are associated with high immune infiltrates and good prognosis. Metastatic MSI tumors result from tumor escape to the immune system and are associated with poor prognosis and chemoresistance. Consequently, immune checkpoint inhibitors (ICI) are highly effective and have recently been approved in dMMR/MSI metastatic colorectal cancers (mCRC). Nevertheless, some patients with dMMR/MSI mCRC have primary or secondary resistance to ICI. This review details carcinogenesis and the mechanisms through which MSI can activate the immune system. After which, we discuss mechanistic hypotheses in an attempt to explain primary and secondary resistances to ICI and emerging strategies being developed to overcome this phenomenon by targeting other immune checkpoints or through vaccination and modification of microbiota.https://www.mdpi.com/2072-6694/13/12/3063microsatellite instabilitycolorectal cancerdeficient mismatch repairimmune checkpoint inhibitorimmunotherapymicrobiota |
| spellingShingle | Violaine Randrian Camille Evrard David Tougeron Microsatellite Instability in Colorectal Cancers: Carcinogenesis, Neo-Antigens, Immuno-Resistance and Emerging Therapies Cancers microsatellite instability colorectal cancer deficient mismatch repair immune checkpoint inhibitor immunotherapy microbiota |
| title | Microsatellite Instability in Colorectal Cancers: Carcinogenesis, Neo-Antigens, Immuno-Resistance and Emerging Therapies |
| title_full | Microsatellite Instability in Colorectal Cancers: Carcinogenesis, Neo-Antigens, Immuno-Resistance and Emerging Therapies |
| title_fullStr | Microsatellite Instability in Colorectal Cancers: Carcinogenesis, Neo-Antigens, Immuno-Resistance and Emerging Therapies |
| title_full_unstemmed | Microsatellite Instability in Colorectal Cancers: Carcinogenesis, Neo-Antigens, Immuno-Resistance and Emerging Therapies |
| title_short | Microsatellite Instability in Colorectal Cancers: Carcinogenesis, Neo-Antigens, Immuno-Resistance and Emerging Therapies |
| title_sort | microsatellite instability in colorectal cancers carcinogenesis neo antigens immuno resistance and emerging therapies |
| topic | microsatellite instability colorectal cancer deficient mismatch repair immune checkpoint inhibitor immunotherapy microbiota |
| url | https://www.mdpi.com/2072-6694/13/12/3063 |
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