['To investigate whether anemia, a putative factor counteracting the efficacy of radiotherapy, up-regulates the endogenous markers of intratumoral hypoxia, the hypoxia inducible factors HIF1 alpha and HIF2 alpha.', 'Forty-two hysterectomy specimens harboring endometrial adenocarcinomas of the endometrioid cell type, stage I were investigated immunohistochemically for the expression of HIF1 alpha, HIF2 alpha and the down-stream inducible expression of vascular endothelial growth factor VEGF. The results were correlated with hemoglobin (Hb) levels.', 'There was no significant association between Hb levels and the expression of HIF1 alpha, HIF2 alpha or VEGF in our material.'] Is hypoxia inducible factor 1 alpha and 2 alpha expression independent of anemia in patients with stage I endometrial cancer?