Microsatellite Instability In Ovarian Invasive And Borderline Epithelial Tumors And Comparison With Prognostic Parameters

Aim: Ovarian cancers, 20% of which are hereditary, are considered the most lethal gynecological malignancies. Defects on DNA mismatch repair (MMR) genes are responsible for hereditary ovarian tumors related with Lynch syndrome. In this study, we aimed to determine microsatellite instability status in invasive and borderline epithelial ovarian tumors diagnosed via immunohistochemistry in our clinic and compare the results with several prognostic parameters and survival.Methods: In this retrospective study, 159 epithelial ovarian tumors were evaluated for age, tumor type, histological grade and Federation of Gynecology and Obstetrics (FIGO) stage as well as survival. MMR protein expression was immunohistochemically examined and absence of nuclear staining in tumor cells was considered MMR protein expression loss. All prognostic parameters were compared and analysed statistically.Results: MMR protein expression loss showed no statistically significant relationship with FIGO stage, age, histological grade, and survival. The only correlation was detected between tumor type and MMR protein loss (p<0.001).Conclusion: Although there are studies comparing microsatellite instability status of the tumors with several prognostic parameters, there is still no consensus on the issue. In this study on ovarian tumors, MMR protein expression loss was related with histological subtypes, but not with other prognostic parameters or survival. We believe that it is worth further investigating in larger studies with higher number of cases.