In this Ask the Expert web chat, Ruben A. Mesa, MD, provides an overview of polycythemia vera and answered our questions. Dr. Mesa is a medical oncologist at the Mayo Clinic in Scottsdale, AZ. He is committed to improving therapies and quality of life for patients with myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and myelofibrosis. Click here (http://www.mayo.edu/research/faculty/...) for Dr. Mesa’s bio.