Acquired somatic MMR deficiency is a major cause of MSI tumor in patients suspected for 'Lynch-like syndrome' including young patients
Autor: | Cedrick Lefol, Christian Baudet, Pierre Naïbo, Qing Wang, Emilie Sohier, Chloé Grand-Masson, Alain Viari, Eric Ruano |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
Adult
congenital hereditary and neonatal diseases and abnormalities Somatic cell Adenomatous Polyposis Coli Protein Loss of Heterozygosity MLH1 DNA Mismatch Repair Germline Article Malignant transformation Loss of heterozygosity Genetics medicine Humans Gene Genetics (clinical) Aged business.industry Microsatellite instability Middle Aged medicine.disease Colorectal Neoplasms Hereditary Nonpolyposis digestive system diseases MutS Homolog 2 Protein MSH2 Cancer research Microsatellite Instability business MutL Protein Homolog 1 |
Zdroj: | Eur J Hum Genet |
Popis: | Patients with tumors displaying high microsatellite instability (MSI-H) but no germline MMR inactivation are suspected for Lynch-like syndrome (LLS). To explore the involvement of acquired somatic MMR alteration as a cause, we screened 113 patient tumor samples for MMR gene variations and loss of heterozygosity. Somatic MMR alterations were found in 85.8% of patients including "double hits" in 63.7% of patients, mainly diagnosed with colon and endometrial cancers. Interestingly, 37.5% of them were under the age of 50, and seven patients were under 30. Somatic alterations were mainly attributed to the MLH1, MSH2 genes, likely reflecting the functional importance of these key MMR genes. Pathogenic variants co-existed in other cancer genes in particular the APC gene displaying a characteristic MMR deficiency-related "mutational signature", indicating that it may be inactivated owing to MMR deficiency. We speculated that APC inactivation could trigger an accelerated malignant transformation underlying early-onset cancers. Our findings provide further insight into the mechanisms underlying LLS, somatic MMR inactivation being a major cause for early-onset LLS through pathways differing from those involved in late-onset sporadic cases. |
Databáze: | OpenAIRE |
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