HIF1A and invasive breast carcinoma: To test whether the CpG and non-CpG methylation differentially affects HIF-1α activity in non-invasive breast cancer and invasive breast cancer cells, the luciferase activity assays were further detected in MCF-7 and MDA-MB-231 cells by co-transfecting 6XHRE reporter vector and a Renilla luciferase plasmid.