SP1 and breast adenocarcinoma: ChIP assays verified that HG increased the binding of Sp1 with the claudin-1 promoter in the region −284 to −84 bp in SMG-C6 cells, in which the binding site for Sp1 in the claudin-1 promoter was similar to others in intestinal epithelial cells and human breast adenocarcinoma cell line MCF-7 (−133 to −61 bp and −138 to −76 bp) [51,52].