In breast cancer cell lines, OPN induced mesenchymal phenotype by the upregulation and downregulation of several mesenchymal (N-cadherin, vimentin, TWIST, and SLUG) and epithelial (E-cadherin and keratin-18) markers, respectively, through noncanonical regulation of GLI1 (discussed in Section 3.5). This evidence concerns the gene SPP1 and breast cancer.