Alterations in the expression of the DNA repair/redox enzyme APE/ref-1 in epithelial ovarian cancers

The DNA base excision repair (BER) pathway is responsible for the repair of cellular alkylation and oxidative DNA damage. A crucial step in the BER pa thway involves the cleavage of an apurinic/apyrimidinic site in DNA by an A P endonuclease. The major AP endonuclease in mammalian cells is APE/ref-1. We studied the expression of APE/ref-1 in formalin-fixed, paraffin-embedded ovarian tissue specimens using polyclonal and monoclonal antibodies to APE /ref-1. Compared to normal ovarian tissues, benign neoplastic conditions, a nd low malignant potential tumors, APE/ref-1 immunoreactivity is altered in malignant ovarian tumors. Further studies will determine if the altered ex pression reflects changes in DNA repair capabilities or redox regulatory fu nctions.