IL3 and neoplasm: Since thrombopoietic cytokines, such as thrombopoietin (TPO) and interleukin-3 (IL-3), enhance VEGF-A expression in megakaryocytes, and, as is the case for TPO, in parallel with megakaryocytic differentiation, we hypothesised that IL-6 derived from primary tumour cells as well as from disseminated tumour cells might enhance VEGF-A expression in platelet progenitors much in the same manner (Imai et al, 1991; Mohle et al, 1997; Bobik et al, 1998; Salgado et al, 1999).