I have ET, and have tested negative for the JAC2. I've been taking Hydrea 500mg for almost 20 years. Still waiting for the day I get the news I may have acute leukemia. My hematologist says taking it every other day is not good enough because that keeps my platelets only at around 520. He wants me at below 500. I tried not taking it, but my platelet count went back up to 800s. For years I have hoped a cure for Essential Thrombocythemia would come along, but still waiting.