To further explore whether CpG and non CpG methylation within the HIF-1α gene promoter may determine the HIF-1α expression level in breast cancer cell lines, we detected and analyzed the CpG and non CpG methylation status of the HIF-1α promoter in MCF-7 after 5-Aza treatment (Fig. 2e). This evidence concerns the gene HIF1A and breast carcinoma.