Previously, Gooding et al. studied three murine specific MM endosteal niche populations including osteoprogenitors (Alcam + Sca1+), stromal progenitors (Sca1 + Alcam-), and endothelial cells (CD31+), and highlighted stromal precursor’ BMP signaling in MM survival [5]. The gene discussed is PECAM1; the disease is Miyoshi myopathy.