title: Anaplastic histology Wilms' tumors registered to the Japan Wilms' Tumor Study Group are less aggressive than that in the National Wilms' Tumor Study 5.
abstract: OBJECTIVE
  To evaluate the clinical features and treatment results of anaplastic histology (AH) Wilms' tumor (WT) patients registered in the Japan Wilms' Tumor Study (JWiTS) group to elucidate the clinical characteristics of AH in the Japanese population.
  
  
  METHODS
  Of 344 WT patients who were enrolled in JWiTS between 1995 and 2013, 17 had AH. Treatment using the JWiTS protocols was similar to the fifth National Wilms' Tumor Study 5 (NWTS-5) protocols. Clinical characteristics and mutation status of TP53 gene were evaluated and compared with those in NWST-5 study.
  
  
  RESULTS
  AH incidences in JWiTS were 4.9 %, lower than that in NWTS-5. Seven tumors had focal AH and 10 had diffuse AH. Clinical stages of AH patients were stage I in seven, stage II in three, stage III in five, stage IV in one and unknown in one. Four-year event-free survival and overall survival rates were 90.9 and 86.7 %, respectively. Two patients with diffuse AH and none with focal AH had TP53 mutation.
  
  
  CONCLUSIONS
  Japanese patients presented with higher incidence, earlier stages and may have better outcomes than American patients, indicating a possible biological heterogeneity of AH WT. Further analysis is necessary to elucidate the different characteristic of AH WT between Japanese and American populations.
authors.affiliation: Department of Pediatric Surgery, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 63-8501, Japan. ta-oue@hyo-med.ac.jp.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Oue
authors.affiliation: Department of Pediatric Surgery, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan.
authors.forename: Tsugumichi
authors.initials: T
authors.lastname: Koshinaga
authors.affiliation: Division of Registration and Research for Childhood Cancer, National Center for Child Health and Development, Setagaya-ku, Tokyo, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Takimoto
authors.affiliation: Department of Pathology, Keio University, Shinjyuku-ku, Tokyo, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Okita
authors.affiliation: Department of Pathology, Kanagawa Children's Medical Center, Yokohama, Kanagawa, Japan.
authors.forename: Yukichi
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Radiology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama, Japan.
authors.forename: Miwako
authors.initials: M
authors.lastname: Nozaki
authors.affiliation: Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Saitama, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Haruta
authors.affiliation: Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Saitama, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kaneko
authors.affiliation: Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fukuzawa
mesh_terms: D000708:Anaplasia; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007564:Japan / Q000453:epidemiology; D007668:Kidney / Q000473:pathology*; D007680:Kidney Neoplasms / Q000401:mortality / Q000473:pathology*; D008297:Male; D009367:Neoplasm Staging; D012042:Registries; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D009396:Wilms Tumor / Q000401:mortality / Q000473:pathology*
chemical_list: C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53
keywords: Anaplastic; JWiTS; NWTS; TP53 mutation; Wilms’ tumor