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