title: The possibility of 'de novo' cancer in the prostate.
abstract: BACKGROUND
  To investigate the possibility of 'de novo' prostate cancer by analyzing the relationship between high grade prostatic intraepithelial neoplasia (HGPIN) and latent prostate cancer.
  
  
  METHODS
  Latent prostate cancers found at autopsy were examined and 55 cancer foci with a poorly (Gleason grade 4 and 5) or moderately (Gleason grade 3) differentiated component were selected. The 55 foci were separated into two groups: (i) foci with either a poorly or moderately differentiated component only (single differentiation group, SDG); and (ii) mixed foci with two or more types of differentiation components (mixed differentiation group, MDG). High grade intraepithelial neoplasia was defined as positive if it was observed within 2 mm from the edge of the cancer focus and the relationship between HGPIN and the two groups was investigated.
  
  
  RESULTS
  The MDG had 39 cancer foci (71.0%) and there were 16 in the SDG (29.0%). There were 31 foci that were small-volume cancers (<0.2 mL). In the MDG, 13 small-volume cancer foci were HGPIN positive, but in the SDG, none of the small-volume cancers were HGPIN positive.
  
  
  CONCLUSIONS
  Small-volume cancer foci without HGPIN in the SDG may be candidates for de novo prostate cancers.
authors.affiliation: Department of Urology, Tokyo Medical University, Tokyo, Japan. shinya.yamamoto@ifcr.or.jp
authors.forename: Shinya
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Takaaki
authors.initials: T
authors.lastname: Ito
authors.forename: Taku
authors.initials: T
authors.lastname: Aizawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Miki
authors.forename: Masakuni
authors.initials: M
authors.lastname: Furusato
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D001344:Autopsy; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D019048:Prostatic Intraepithelial Neoplasia / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000473:pathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index