Diagnostic Utility o PAX8 in differentiation of Mullerian from Nonmullerian Tumors

Introduction: Considering the high prevalence of female genital tract neoplasms, nonspecificnature of the initial symptoms, the higher possibility of metastasis by the time of diagnosis,importance of differentiating metastatic tumors from breast cancer or metastatic breastcancer in female genital track specially in ovary and lack of diagnostic markers with highsensitivity and specificity, the purpose of current study was to evaluate the utility of Pairedbox protein8 (PAX8) expression in mullerian and nonmullerian neoplasms.Methods: In this descriptive-analytic, cross sectional study, paraffin-embedded tissues ofpatients with definitive pathologic diagnosis of mullerian and non-mullerian tumors wereselected. PAX8 immunohistochemical (IHC) staining was performed for all selected blocks.Immunopositivity of the slides for PAX8 was reviewed. It was defined as the presence ofnuclear staining in at least 10% of tumor cell nuclei.Results: 37 mullerian and 37 non-mullerian tumors were studied for PAX8 expression.29/37(78.4%) and 1/37(2.7%) of mullerian and non-mullerian tumors were positive forPAX8, respectively. The sensitivity and specificity of PAX8 by IHC for differentiation ofmullerian from non-mullerian Tumors was 78.4% and 97.3% respectively.Conclusion: Our findings indicated that PAX8 could be used as a usefulimmunohistochemical marker for diagnosing of mullerian tumors. It has moderate to highsensitivity, but high specificity for diagnosing carcinomas of mullerian origin.

Diagnostic Utility o PAX8 in differentiation of Mullerian from Nonmullerian Tumors Keywords:

PAX8 , Mullerian , Immunohistochemical staining , Female , genital tract , Tumor