b'Environmental Exposure LinkedTo Blood Cancer Risk in Veterans Study Shows Link Between Agent Orange and MPNsA recent study has linked the development of polycythemia vera and other MPNsessential thrombocythemia (ET) and primary myelofibrosis (MF)with exposure to the herbicide Agent Orange. Among patients with MPNs, researchers reported, the likelihood of exposure to Agent Orange was 1.63 times higher compared to the exposure odds among controls.By Mary Anne DunkinWASHINGTON, DCOne of a group of rare bloodOrange and PCV and other MPNs.disordersknownasmyeloproliferativeneoplasmsToconductthestudy,researchersledby Andrew (MPNs), polycythemia vera (PV) is characterized byTiu,MD,asecond-yearhematology/oncologyfel-elevated absolute red blood cell mass due to uncon- lowwithMedstarGeorgetownUniversityHospital trolled red blood cell production. In most patients,inWashington,DC,usedtheVAInformaticsand the production of white blood cells and platelets areComputing Infrastructure (VINCI) database to ana-also elevated. If not controlled, this proliferation canlyzethemedicalrecordsof93,269MPNpatients lead to blood clots resulting in stroke and organ andfromapoolof12,352,664veteransspanning17 tissue damage.years. To establish a comparative baseline, veterans A mutation of the Janus kinase 2 gene (JAK2) isfrom Illinois were included as a control group, chosen thought to be the most likely source of PCV patho- for its strong representativeness of the broader U.S. genesis. More than 90% of individuals with PCVpopulation, as per data from the U.S. Census Bureau.have a mutation in the JAK2 gene. The exact role JAK2mutationsplayinthedevelopmentofPCVKey findings included: or what causes the mutations is not known, but a Among patients with MPNs, the likelihood of recentstudylinksthedevelopmentofPCVandexposure to Agent Orange was 1.63 times higher other MPNsessential thrombocythemia (ET) andcompared to the exposure odds among controls.primary myelofibrosis (MF)with exposure to the When comparing individuals with MPNs to herbicide Agent Orange.1 controls matched for age, gender, and race, there Namedfortheorangebandaroundthebarrelinwere higher incidences of arterial clotting (37% which it was stored, Agent Orange was a tactical her- vs. 18.5%), venous clotting (14.8% vs. 5.2%), bicide used by the U.S. military to control vegetationand bleeding events (39.1% vs. 13.5%) among during the Vietnam War. The VA has recognized cer- the MPN patients, respectively.tain types of cancers and other diseasesincluding People with MPNs were more likely to have bladder cancer, Type 2 diabetes mellitus, hyperten- hypertension (75.5% vs 43.2%), diabetes sion and Hodgkins diseaseas presumptive diseases(31.2% vs 19%) and heart failure (26.1% vs associated with exposure to Agent Orange or other11%) than age-, gender- and race-matched herbicidesduringmilitaryservice.Buttherecentcontrols, respectively.study is the first to show an association between Agent The odds of Agent Orange exposure among 72'