CDKN1B and breast carcinoma: Recently, it has been demonstrated that a subset of periarteriolar MSCs with a neuronal glial antigen 2 (NG2)+, Nestin+ phenotype produce TGF-β2 and BMP-7 to activate a quiescence pathway in metastatic breast cancer cells by inducing cyclin-dependent kinase inhibitor 1B (CDKN1B) via MAPK activation [102].