The Prevalence and Associated Factors of Microsatellite Instability in Ovarian Epithelial Cancers Detected by Molecular Genetic Studies in a Sample of Iranian Women

Background: Microsatellite instability, the main genetic element in HNPCC syndrome, is associated with a number of cancers, including ovarian epithelial carcinomas. These cancers have distinct characteristics compared to non-MSI related ones. Objectives: The present study aims at determining the prevalence of microsatellite instability in ovarian carcinomas and their associated factors in Iranian patients. Methods: Paraffin-embedded blocks, belonging to 37 patients with definite diagnosis of ovarian epithelial cancers, were retrieved from the archives. After DNA extraction from tumor tissue and PCR reaction, the results were assessed in accordance with melting curve analysis. Subsequently, the relationship among microsatellite status and tumor histology, grade, stage, and size were investigated statistically. Results: The predominant histological type was serous histology. Four out of 37 carcinomas were microsatellite unstable (10.8%) and only 1 was MSI-high type (2.1%). The MSI was more frequent among younger patients with unilateral, non-serous histology, nonhigh grade, and stage I tumors without omental involvement. After statistical analysis, the only significant relationship was found between histological type (non-serous) and microsatellite status. Conclusions: Microsatellite stable and unstable ovarian cancers may have different associations with various factors in a sample of Iranian women. The identification of these characteristics may help narrow down indications to test this prognostic and predictive genetic error.