DNA repair-redox enzyme apurinic endonuclease in cervical cancer: Evaluation of redox control of HIF-1 alpha and prognostic significance

The multifunctional apurinic/apyrimidinic endonuclease (Ape1/ref-1) plays a key role in the human DNA base excision repair pathway. Ape1/ref-1 has als o been shown to be involved in the redox control of transactivation activit ies of hypoxia-inducible factor (HIF)-1 alpha. The aim of our study was to investigate the expression of these proteins in early stage invasive cervic al cancer. Expression of Ape1/ref-1 and HIF-1 alpha was detected immunohist ochemically in 88 samples of cervical cancer stage pT1b. The levels of the proteins were compared and the prognostic influence of Ape1/ref-1 expressio n was investigated. Strong nuclear expression of Ape1/ref-1 was observed in 9 cases (10.2%), moderate in 22 cases (25%), weak in 17 cases (19.3%), and absent in 40 cases (45.5%). Furthermore, no correlation between Ape1/ref-1 and HIF-1 alpha expression was observed (p=0.864). We also found no relati onship of Ape1/ref-1 expression and survival (p >0.05, log-rank test). From these studies, we have concluded that in cervical cancer there is no corre lation between the upstream redox regulatory protein of HIF-1, i.e., Ape1/r ef-1, and HIF-1 alpha expression. However, these studies do not address any functional relationship between the two proteins.