A. MCF-7 were implanted into nude mice (n = 5/group) and allowed to grow up to ~ 200mg, when treatment with AF (60 mg/kg daily × 4 days i.p.) was started. Tumor weight was measured as described in Materials and Methods, (Mann-Whitney test; *, p < 0.01). B. Quantitative determination of HIF-1α protein levels (**, p <0.05). C. mRNA expression of HIF-1-target genes (VEGF, CA9 and PDK-1) in tumor lysates from mice treated with vehicle or AF were assessed (p < 0.05). Values are expressed as fold change relative to levels detected in mRNA harvested from normoxic MCF-7.