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

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


Methods
: A total of 102 cases were selected including 50 adenomatous polyps, 25 adenocarcinomas, 10 adenocarcinomas with mucinous component, 14 mucinous adenocarcinomas and 3 signet ring cell carcinomas.  These 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 NOS and mucinous adenocarcinomas, 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. 69.2 % of the MLH1 negative cases were high grade. There was a statistically significant relationship between 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 microsatellit instability.

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AVES | Copyright © 2018 European Journal of Therapeutics | Latest Update: 09.10.2018