CDKN1A and breast carcinoma: In this regard, in vitro and in vivo experimental studies have recently demonstrated that WISP-1 not only promotes growth of human breast cancer cells by downregulating a tumor suppressor (N-myc downstream-regulated gene 1) and cell-cycle inhibitors (cyclin-dependent kinase inhibitors 1 and 1B), but that it also encourages metastatic potential by stimulating epithelial to mesenchymal transition traits.