Apurinic/apyrimidinic endonuclease expression in pediatric yolk sac tumors

Background: The enzyme apurinic/apyriminidic endonuclease/redox factor 1 (Ape1/ref1), a key protein in the base excision repair pathway, displays repair and redox activity. We examined the role of Ape1/ref1 and a protein it regulates, hypoxia inducible factor 1 alpha (HIF-1α) in pediatric yolk sac tumors. Patients and Methods: Using an immunohistochemical evaluation, 16 pediatric yolk sac tumors were evaluated for Ape1/ref1 and HIF-1α expression. Samples were obtained from archival tissue. Results: We demonstrated high levels of expression of Ape1/ref1 in 14/16 of the tumors. This expression was limited to the nucleus of the viable portion of each tumor. High levels of HIF-1α expression was noted in half of the same tumors and localized to both the nucleus and cytoplasm of the viable tumor. Conclusions: The high levels of expression of Ape1/ref1 in this group of chemosensitive tumors may be related to the subcellular location or redox regulatory activity of one of the other factors controlled by Ape1/ref1.