Illustration of a dendritic cell (white) recognising a multiple myeloma cancer cell (translucent with dark purple organelles). Multiple myeloma is a type of cancer that occurs when a type of white blood cell called a plasma cell becomes abnormal and cancerous. The cancerous plasma cell divides and multiplies creating large amounts of abnormal antibodies. Dendritic cells are a type of white blood cell. The primary role of dendritic cells is presenting antigens, substances from pathogens or irregular host cells that stimulate an immune response, to other white blood cells. In the background are healthy red blood cells (red) and white blood cells (translucent).