[1] Tohoku Univ, IDAC, Dept Clin Oncol, Sendai, Miyagi 980, Japan
[2] Tohoku Univ Hosp, Dept Clin Oncol, Sendai, Miyagi, Japan
[3] Osaki Citizen Hosp, Dept Clin Oncol, Osaka, Japan
[4] Akita Univ, Grad Sch Med, Akita 010, Japan
[5] Tohoku Univ, Grad Sch Med, Dept Med Stat, Sendai, Miyagi 980, Japan
[6] Tohoku Univ, Dept Pathol, Sendai, Miyagi 980, Japan
[7] Yamagata Univ, Yamagata 990, Japan
[8] Yamagata Pref Cent Hosp, Yamagata, Japan