SP1 and breast cancer: To identify previously unreported transcription factors that regulate VEGF transcription, we used VEGF promoter (from −2304 to +73 bp) fused with a gene encoding luciferase as a reporter (VEGF-Luc) to screen a transcription factor genome-wide full-length cDNA-transfection (GFC-transfection) array, consisting of 704 transfection-ready cDNA plasmids, and identified some transcription factors that stimulated the reporter gene expression in ZR75-1 breast cancer cells (Figure 1A, 1B; data not shown), such as DEK and the previously reported transcription factors SP1 and HIF1α [36, 37].