PV EBs – DXM vs PV EBs + DXM. This comparison revealed increased activation of RTKs (KIT, EGFR, ErbB2, VEGFR, PDGFR and Met) and of the SAPK/JNK pathway in PV + DXM while PV– DXM were characterized by increased activation of Raf/MSK1/RSK3 and STAT3 and STAT5.