Apurinic/apyrimidinic endonuclease expression in pediatric yolk sac tumors

Background: The enzyme apurinic/apyriminidic endonuclease/redoxx factor 1 ( Ape1/ref1), a key protein in the base excision repair pathway, displays rep air and redox activity. We examined the role of Ape1/ref1 and a protein it regulates, hypoxia inducible factor 1 alpha (HIF-1 alpha) in pediatric yolk sac tumors. Patients and Methods: Using an immunohistochemical evaluation, 16 pediatric yolk sac tumors were evaluated for Ape1/ref1 and HIF-1 alpha expression. Samples were obtained fi om archival tissue. Results: We demons trated-high levels of expression of Apel1/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-1 alpha expression was noted in half of the same tumors and localized to both the nucleus and cytoplasm of the viable tumor. Concl usions: The high levels of expression of Ape1/ref1 in this group Of chemose nsitive tumors may be related to the subcellular location ar redox regulato ry activity of one of the other factors controlled by Ape1/ref1.