ISSN 2564-7784 | E-ISSN 2564-7040
Original Article
Evaluation of Microsatellite Instability in Colorectal Adenomas and Carcinomas by Immunohistochemistry and a Comparison of Histopathological Features
1 Department of Pathology, Recep Tayyip Erdoğan University, School of Medicine, Rize, Turkey  
2 Department of Gastroenterology, Recep Tayyip Erdoğan University, School of Medicine, Rize, Turkey  
3 Department of General Surgery, Recep Tayyip Erdoğan University, School of Medicine, Rize, Turkey  
Eur J Ther 2019; 25: 28-38
DOI: 10.5152/EurJTher.2018.582
Key Words: Adenomatous polyps, colorectal carcinomas, immunohistochemistry, microsatellite instability
Abstract

 

Objective: Approximately 15% of sporadic colorectal carcinomas (CRCs) develop along the microsatellite instability (MSI) pathway. In this study, we compared the MLH1, MSH2, Ki-67, and p53 immunostaining properties with histopathological features of colorectal adenomas and CRCs.

 

Methods: A total of 102 cases were selected, including 50 adenomatous polyps, 25 adenocarcinomas, 10 adenocarcinomas with mucinous component, 14 mucinous adenocarcinomas, and three signet-ring cell carcinomas. The tissues were stained for MLH1, MSH2, p53, and Ki-67 primary antibodies.

 

Results: Negative staining was observed for MLH1 in 25% and MSH2 in 3.8% of all CRC cases. Compared with adenocarcinoma not otherwise specified (NOS), mucinous adenocarcinomas showed weaker staining for MLH1, which was statistically significant. There was also a statistically significant difference between adenocarcinoma NOS and signet-ring cell carcinomas in terms of negative staining for MLH1. A total of 69.2% of the MLH1-negative cases were high-grade. There was a statistically significant relationship between the histological grade and MLH1 negativity. A positive correlation was found between the grade of dysplasia and p53 staining intensity and Ki-67 proliferation index. No negative staining was observed for MLH1 and MSH2 in any of the adenomatous polyps.

 

Conclusion: For the histopathological examination of CRCs, in the presence of mucinous and poorly differentiated morphology, tumor-infiltrating lymphocytes and Crohn-like inflammatory response, immunohistochemical staining for MLH1, and MSH2 antibodies may be useful in the detection of tumors showing MSI.

 

 

How to citeYılmaz R, Bedir R, Akdoğan RA, Pergel A. Evaluation of Microsatellite Instability in Colorectal Adenomas and Carcinomas by Immunohistochemistry and a Comparison of Histopathological Features. Eur J Ther 2019; 25(1): 28-38.

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AVES | Copyright © 2019 European Journal of Therapeutics | Latest Update: 28.05.2019