Next-generation sequencing and immunohistochemistry approaches for microsatellite instability detection in endometrial cancer.

Abstract

The purpose was to determine the effectiveness of immunohistochemical observation, a quick and easy method for determining Microsatellite instability MSI and/or other types of endometrial cancer (EC) based on modern classification. As molecular study takes more cost we want to compare both methods and show the possibility of doing IHC instead of molecular study. This study was designed to establish a small gene panel of Next Generation Sequencing (NGS) of endometrial cancer patients targeting 4 mismatch repair genes; MSH6, MSH2, MLH1 and PMS2. Using the DNBSEQ-G400 Platform, the Human Core Exome kit and Python software for analysis were used. At the same time, the Dako kit was used to perform IHC for six primary antibodies used to detect each of MSH6, MSH2, MLH and PMS2. The primary antibodies were applied on 5 µm formalin-fixed paraffin-embedded (FFPE). Results showed that histopathological examinations of all patients were at stage I endometrioid endometrial carcinoma. The FIGO classifications were Ia and Ib. Microsatellite instability (MIS) was observed through the IHC study. The molecular studies detected several polymorphisms that have clinical significance and some of them have conflicting interpretations. In conclusion, we considered that a simple immunoreaction staining procedure can be used as an alternative method for MSI phenotype detection rather than any type of more expensive and complex method of NGS.