The emerging picture shows commonalities between different cell types, where signaling molecules/pathways triggered by reverse MHC-I signaling are shared: Fps and SHP-2 as early events in macrophages and epithelial cells (9, 94); the involvement of STAT proteins in macrophages and T-cells (6, 80); JNK in NK cells and tumor cells (52, 127); Akt and ERK1/2 signaling in endothelial cells (106, 108, 110–113, 115), smooth muscle cells (124, 126), and myeloma cells (127); and an inhibition or activation of NF-κB in macrophages, NK cells, T cells and epithelial cells (9, 52, 85, 94) (Tables 1–7). Here, MAPK3 is linked to plasma cell myeloma.