Evaluation of microsatellite instability in routine examinations of surgical samples
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Date
2022-03
Journal Title
Journal ISSN
Volume Title
Publisher
Wolters Kluwer - Medknow
Abstract
Context: Approximately 20%–30% of colon cancer cases have a hereditary basis. The genetic defect may involve mismatch repair (MMR) genes, which results in microsatellite instability (MSI). MMR-deficient colorectal cancer may occur due to germline mutation (Lynch syndrome) or be a sporadic one. A tumor's histological features, supported by a panel of immunohistochemistry stains, enables pathologists to assess the MMR status, which in turn has beneficial effects on clinical management. Aims: We aimed to show the relations between histopathological features identified during routine examinations and MMR genes' mutations. Methods and Material: We reviewed retrospectively the material of the Department of Pathology fulfilling the revised Bethesda Guidelines. Statistical Analysis Used: We used Chi-square test, Spearman test, and epidemiological analysis. Results: For the PMS2 gene, the positive predictive value (PPV) indicates that 91% of cases neither present any histological lesions nor have genetic abnormalities. The negative predictive value (NPV) indicates that only 50% of cases have both histological and genetic changes. For the MSH6 gene, the PPV indicates that 85% of tumors without specific histological features do not have genetic abnormalities. Conclusions: We advise universal staining for MLH1, MSH2, MSH6, and PMS2 in every newly diagnosed colon cancer, but due to costly analyses we suggest a protocol for the selection of cases for MMR examinations.
Description
Keywords
Colorectal carcinoma (CRC), lynch syndrome (LS), microsatellite instability (MSI), mismatch repair (MMR)
Citation
Wlaszczuk P, Kuzbinska A, Dobrosz Z, Palen P, Pawlicki K.. Evaluation of microsatellite instability in routine examinations of surgical samples. Indian Journal of Pathology & Microbiology. 2022 Mar; 65(1): 87-92