Growth factors of the PDGF and FGF families act through receptor tyrosine kinases. These receptors can be activated by chromosomal rearrangements in myeloid neoplasms associated with hypereosinophilia. We identified a new fusion gene between KANK1 and PDGFRbeta in a patient with thrombocythemia. We showed that such fusion oncoproteins derived from PDGF and FGF receptors escape the normal degradation pathways, leading to their accumulation in cells. This process amplifies signalling leading to cell proliferation. Using microarrays and bioinformatics, we showed that several transcription factors contribute to the control cell growth, including STATS, FOXO and SREBP.