Evaluation of Concordance Between Deficient Mismatch Repair and Microsatellite Instability Testing and Their Association with Clinicopathological Features in Colorectal Cancer

• Main Authors: Bai H, Wang R, Cheng W, Shen Y, Li H, Xia W, Ding Z, Zhang Y
• Format: Article
• Language: English
• Published: Dove Medical Press 2020-04-01
• Series: Cancer Management and Research
• Subjects: deficient mismatch repair; microsatellite instability; clinicopathological features; colorectal cancer.
• Online Access: https://www.dovepress.com/evaluation-of-concordance-between-deficient-mismatch-repair-and-micros-peer-reviewed-article-CMAR

Huili Bai,1,* Rong Wang,1,2,* Wei Cheng,1 Yifan Shen,1 Haijun Li,2 Wei Xia,1 Zhenglin Ding,3,* Yuhong Zhang1,* 1The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China; 2Department of Laboratory Medicine, Guangyuan Central Hospital, Guangyuan, Sichuan, People’s Republic of China; 3Department of Laboratory Medicine, The People’s Hospital of Nanchuan, Chongqing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yuhong Zhang; Zhenglin Ding Email [e-mail]; [e-mail]: Microsatellite instability (MSI) is one of the most important molecular characteristics of colorectal cancer (CRC), which mainly results from defective DNA mismatch repair (MMR). This study was performed to investigate the concordance between deficient MMR and MSI testing, and to evaluate the association of these two results with clinicopathological characteristics in Chinese CRC patients.Methods: A total of 738 CRC patients were included. Tumor tissues and paired peripheral blood specimens were obtained. Screening for MMR was investigated using immunohistochemical (IHC) technique, and multiple polymerase chain reaction-capillary electrophoresis (PCR-CE) method was performed to detect the MSI status. All clinicopathological data, immunohistochemistry and microsatellite instability analyses were then statistically analyzed.Results: Of the 738 (17.75%) CRC patients, 131 expressed as deficient mismatch repair (dMMR) status, and postmeiotic segregation increased 2 (PMS2) deficiency was the most frequent deficiency among these four MMR proteins. MSI-high (MSI-H) status occurred in 74 of the 738 (10.03%) CRC patients, 55 of whom showed instability at all six mononucleotides repeat markers. dMMR was significantly associated with MSI-H and moderate concordance was observed between IHC and PCR-CE in evaluating deficient MMR/MSI through Kappa test. Statistically, dMMR was significantly associated with younger age, right-sided colon and poor differentiation. MSI-H was associated with younger age, right-sided colon, poor differentiation, mucinous type and tumor, node, metastasis (TNM) stage II.Conclusion: A moderate concordance between deficient MMR and MSI testing indicates that both IHC and PCR-CE methods should be routinely tested to provide reliable data for clinical treatment decisions.Keywords: deficient mismatch repair, microsatellite instability, clinicopathological features, colorectal cancer