[1] Univ Tsukuba, Fac Med, Dept Pediat Surg, Tsukuba, Ibaraki 3058575, Japan
[2] Univ Tsukuba, Fac Med, Dept Pathol, Tsukuba, Ibaraki 3058575, Japan
[3] Saitama Cardiovasc & Resp Ctr, Div Pathol, Saitama, Japan
[4] Saitama Childrens Med Ctr, Div Pathol, Saitama, Japan