CDKN1B and breast carcinoma: Interestingly, the OSGIN1 homolog, bone marrow stromal cell (BMSC)-derived growth inhibitor (BDGI), has been shown to induce cell cycle arrest in S phase and subsequent apoptosis of MCF-7 breast cancer cells, which potentially occurs through upregulation of p27Kip1 and downregulation of cyclin A, Bcl-2, and Bcl-xL [39].