An HGF/Met/IL-11/IL-6/gp130/STAT3 cascade was found to be activated in PV clonal erythroblasts (Figure 2B); activation of a similar autocrine HGF/IL-11/IL-6 cascade has been described in multiple myeloma and in solid tumours [94,115,116,117]. The gene discussed is HGF; the disease is plasma cell myeloma.