[1] Sungkyunkwan Univ, Sch Med, Kangbuk Samsung Hosp, Internal Med, Seoul, South Korea
[2] Seoul Natl Univ, Coll Med, Seoul Natl Univ Hosp, Internal Med, Seoul, South Korea
[3] Catholic Univ Korea, Coll Med, Seoul St Marys Hosp, Hematol,Canc Res Inst, Seoul, South Korea