Cell biological roles of IL-10 in myeloma cells

IL-10, along with interleukin (IL)-6, are considered two of the most important cytokines that regulate the proliferation and cellular characteristics of myeloma cells. It remains unclear from the clinical data how levels of IL-10 in serum at various stages of myeloma are related to clinical manifestations of this disease. Several studies have reported that IL-10 affects myeloma cells by stimulating secondary signals for cell proliferation through oncostatin M (OSM) and IL-11. In experiments using human myeloma cell lines that were established in our laboratory, IL-10 seemed to be expressed in half of myelomas simultaneously with OSM, and was correlated with c-maf, a transcription factor that has been known to be overexpressed in myelomas with t (14; 16) (q32; q23). In addition, IL-10 abolishes all traps-retinoic acid (ATRA)-induced growth inhibition of myeloma cells. The expression and production of IL-10 in myeloma patients may be important for subcategorization and to establish case-oriented therapies.