Provided herein are osteogenic placental adherent cells (OPACs), methods of using OPACs and OPAC populations, and methods of culturing, proliferating, expanding, or differentiating the OPACs. Further provided herein are methods of using the OPACs to formulate implantable or injectable compositions suitable for administration to a subject. Still further provided herein are methods for treating bone defects with OPACs and compositions comprising OPACs. Also provided herein are methods of using OPACs in the treatment and management of multiple myeloma, e.g., reducing the progression of, halting the progression of, or improving, one or more symptoms of multiple myeloma in an individual having multiple myeloma, comprising administering a plurality of OPACs to the individual.