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