Is tumor testing efficiency for Lynch syndrome different in rectal and colon cancer?
Dig Liver Dis
; 52(12): 1503-1511, 2020 12.
Article
en En
| MEDLINE
| ID: mdl-32620519
ABSTRACT
BACKGROUND:
Tumor testing utility in Lynch syndrome (LS) diagnosis is established.AIMS:
Analyze the differences between tumor testing efficiency in rectal (RC) and colon cancer (CC).METHODS:
We performed immunohistochemistry (IHC) for MisMatch Repair (MMR) proteins (IHC-MMR) and MicroSatellite Instability analysis (MSI) on 482 unselected primary tumors 320 CCs and 162 RCs. Samples had proficient-IHC, deficient-IHC or borderline-IHC ("patchy" expression). MSI-H borderline-IHC tumors were considered as likely MMR-deficient. Germline testing was offered to MMR-deficient patients without BRAF mutation or MLH1 promoter hypermetilation (MLH1-Hy).RESULTS:
We identified 51/482 (10.6%) MMR-defective tumors. Multivariable analysis demonstrated a significant correlation between tumor testing results with histotype, lymph-node involvement and tumor location. In particular, RC showed a lower MMR-deficiency rate than CC (p<0.0001). Interestingly, MLH1 loss was detected in 0% RCs and 76.1% CCs, with 80% of them showing BRAF mutation/MLH1-Hy. A germline variant was detected in 12 out of 18 patients (mutation detection rate of 66.7%).CONCLUSION:
Tumor testing results showed molecular differences between CCs and RCs, in terms of MMR proteins expression, and presence of BRAF mutation/MLH1-Hy. MSH6 variants were the most frequent ones (50%). Although young age at diagnosis was associated with mutation detection (pâ¯=â¯0.045), 33.3% of LS patients were >50 years.Palabras clave
Texto completo:
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Banco de datos:
MEDLINE
Asunto principal:
Neoplasias del Recto
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Neoplasias Colorrectales Hereditarias sin Poliposis
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Neoplasias del Colon
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Reparación de la Incompatibilidad de ADN
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Detección Precoz del Cáncer
Tipo de estudio:
Diagnostic_studies
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Prognostic_studies
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Risk_factors_studies
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Screening_studies
Límite:
Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Año:
2020
Tipo del documento:
Article