Mast cells may promote myeloma engraftment in the NSG-hIL6 patient derived xenograft model

Multiple myeloma remains a fatal, incurable disease. Most therapies are targeted to the cancer cell or T cell engagement. Little is known about the supporting myeloma microenvironment and its contribution to tumor fitness. Here, we expand upon the observation of human mast cells in the NSG-hIL6 myeloma patient derived xenograft mouse model to correlate mast cells to decreased engraftment time and increased overall myeloma engraftment. Mast cells may also correlate to worsened bone disease. We identify 10 mast cell secreted factors that together improve the survival of patient myeloma cells in vitro. Our findings demonstrate the utility of the NSG hIL6 model for studying human bone marrow–myeloma crosstalk, including mast cells.