MAPK1 and neoplasm: In MM, as with other p38 inhibitors, the use of LY2228820 exhibited a modest cytotoxic effect on tumor cells, but increased the tumor cytotoxicity of bortezomib and inhibited the secretion of IL-6 from BM stromal cells and BM mononuclear cells (BMMNC) derived from MM patients in remission, and significantly inhibited osteoclastogenesis in vitro and in vivo in a xenographic model of human MM [94].