title: Isolation and detection of label-retaining cells in a nasopharyngeal carcinoma cell line.
abstract: OBJECTIVE
  Detection of label retaining cells (LRCs) has been a method to confirm existence of stem cells, and bromodeoxyuridine (BrdU) has commonly been used for labeling. In this study, to verify stem cells in nasopharyngeal carcinoma (NPC), LRCs were established and detected in NPC cell line 5-8F.
  
  
  METHODS
  The 5-8F cells were cultured with BrdU and inoculated subcutaneously into nude mice. By immunohistochemistry, immunocytochemistry, and immunofluorescence, BrdU was detected in 5-8F cells and xenograft tumors.
  
  
  RESULTS
  BrdU was strongly positive in cells on the 2nd and the 7th day after being added BrdU, while negative when cells were cultured without BrdU. However, only sporadic cells were positive on the 14th day after BrdU being washed out, and these cells were thought to be LRCs. The average percentage of LRCs was (0.67 +/- 0.32)%. After being cultivated with BrdU for 48 h, 5-8F cells were inoculated into nude mice subcutaneously. After chasing 8 weeks, only sporadic LRCs were detected in xenograft tumors, with a proportion of (0.55 +/- 0.36)%, and these LRCs were located at cancer margin.
  
  
  CONCLUSIONS
  The existence of LRCs in 5-8F cells indicates the existence of cancer stem cells in NPC.
authors.affiliation: Cancer Institute, Basic Medicine, Southern Medical University, Guangzhou, Guangdong 510515, PR China.
authors.forename: Qing-Ping
authors.initials: QP
authors.lastname: Jiang
authors.forename: Kai-Tai
authors.initials: KT
authors.lastname: Yao
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism / Q000473:pathology*; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000166:cytology* / Q000378:metabolism
chemical_list: D001973:Bromodeoxyuridine