Matching Pairs polycythemia veraOnline version information about thus blood cancer by Kennedy Ellis 1 drawing blood 2 polycythemai vera 3 what do you experience? 4 the mutation in which gene causes this blood cancer 5 enlarged spleen 6 what does polycythemia cause? heart attack or stroke increased number of red blood cells helps reduce # of RBCs helps fight infection and filter unwanted material and gets bigger when there is too much RBCs janus kinase 2 (JAK2) itchiness, headches, dizziness, bleeding/bruising, weakness, fatigue