[1] Gunma Univ, Grad Sch Med, Dept Gen Surg Sci, Div Hepatobiliary & Pancreat Surg, 3-39-15 Showamachi, Maebashi, Gunma 3718511, Japan
[2] Natl Hosp Org Takasaki Gen Med Ctr, Dept Clin Res, 36 Takamatsucho, Takasaki, Gunma 3700829, Japan
[3] Gunma Univ, Grad Sch Med, Dept Hematol, 3-39-15 Showamachi, Maebashi, Gumma 3718511, Japan