title: Prognostic impact of the cancer stem cell-related marker NANOG in ovarian serous carcinoma.
abstract: OBJECTIVE
  The objective of this study was to evaluate the prognostic significance of NANOG expression in ovarian serous carcinoma.
  
  
  METHODS
  The expression of NANOG was evaluated in 6 ovarian carcinoma cell lines, paclitaxel-resistant SKOV3 cells, and SKOV3 spheroid cells with semiquantitative reverse transcription-polymerase chain reaction and Western blotting. NANOG expression was also measured immunohistochemically in a tissue microarray containing ovarian tissues from 74 patients with ovarian serous carcinoma and 24 with ovarian serous cystadenoma. Each sample was scored based on signal intensity and proportion, and a score greater than 4 was considered "positive."
  
  
  RESULTS
  NANOG mRNA expression was variable in different ovarian cancer cell lines. The mRNA level of NANOG was increased in the paclitaxel-resistant SKOV3 cells and SKOV3 spheroid cells compared with that in the SKOV3 cells. NANOG expression was positive in 21.6% of 74 ovarian serous carcinoma tissues, but none of the ovarian serous cystadenoma tissues were positive. Positive NANOG expression was associated with residual tumor size after surgery (P = 0.032). The overall survival of the patients with positive NANOG expression was poorer than that of the patients with negative NANOG expression (P = 0.020). In patients with stage I and II disease, positive NANOG expression was independently associated with shorter overall survival compared with negative NANOG expression (40 vs 120 months, respectively; P = 0.031).
  
  
  CONCLUSIONS
  Positive NANOG expression is associated with poor prognosis of ovarian serous carcinoma. NANOG has potential as a predictor of survival for patients with ovarian carcinomas and may be involved in the mechanism of chemoresistance.
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Kangdong Sacred Heart Hospital, Hallym University, Seoul, Republic of Korea.
authors.forename: Maria
authors.initials: M
authors.lastname: Lee
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Nam
authors.forename: Sang Wun
authors.initials: SW
authors.lastname: Kim
authors.forename: Sunghoon
authors.initials: S
authors.lastname: Kim
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Young Tae
authors.initials: YT
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D045744:Cell Line, Tumor; D018284:Cystadenocarcinoma, Serous / Q000175:diagnosis* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D000071317:Nanog Homeobox Protein; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D017239:Paclitaxel / Q000627:therapeutic use; D011379:Prognosis; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D017239:Paclitaxel