Endometrial hyperplasia: Paired box-2 immunohistochemistry features in correlation with routine section study

Background: Paired box 2 (PAX2) gene encodes the PAX2 transcription factor, which is essential for the embryonic development of the urogenital tract. PAX2 is expressed in normal endometrium. The aim of this study is to assess the prognostic value of immunohistochemistry analysis of PAX2 expression in endometrial hyperplasia.Materials and Methods: 54 blocks of formalin-fixed paraffin-embedded tissues of endometrial biopsies and hysterectomies, from November 2022 to April 2024, were obtained from the Department of Pathology, Sree Balaji Medical College. Out of these 54 histologically proven cases of endometrial hyperplasia (EH), 36 cases were of EH without atypia and 18 cases were of endometrial hyperplasia with atypia (AH, or atypical hyperplasia).Results: PAX2 expression gradually declines from Endometrial Hyperplasia without atypia to Endometrial Hyperplasia with atypia. This was confirmed by the comparison of PAX2 expression between EH with and without atypia by a chi-square test, which showed a p-value of 0.00 and was proven significant statistically.Conclusion: PAX2 can be used as a sensitive marker that demarcates the premalignant glands, especially in EIN lesions presenting against a secretory background, and also identifies precancerous EH even in the absence of evident cytologic atypia.