The activity of the human SPARC promoter requires a purine-rich region with GGAGG repeats (within the -120/-70 fragment) in human breast cancer MCF7 cell line, and the transactivation of the SPARC promoter is dependent on the transcription factor Sp1/3 in Drosophila SL2 cells [64]. This evidence concerns the gene SPARC and breast carcinoma.