SP1 and breast cancer: MMP-2 transcriptional regulation is part of a delicate balance between the expression of various extracellular matrix (ECM) constituents and ECM-degrading enzymes, and the transcription rate of MMP-2 in BC has been shown to be regulated by Ets1,39 Sp1,40 p-Erk,41 and FOXO17 in several previous publications.