[1] Univ Tsukuba, Dept Med Oncol, Fac Med, Tsukuba, Ibaraki, Japan
[2] Univ Tsukuba, Dept Child Hlth, Fac Med, Tsukuba, Ibaraki, Japan
[3] Univ Tsukuba, Dept Breast & Endocrine Surg, Fac Med, Tsukuba, Ibaraki, Japan
[4] Univ Tsukuba, Dept Neurosurg, Fac Med, Tsukuba, Ibaraki, Japan
[5] Univ Tsukuba, Dept Obstet & Gynecol, Fac Med, Tsukuba, Ibaraki, Japan