title: Expression of HIWI in human esophageal squamous cell carcinoma is significantly associated with poorer prognosis.
abstract: BACKGROUND
  HIWI, the human homologue of Piwi family, is present in CD34+ hematopoietic stem cells and germ cells, but not in well-differentiated cell populations, indicating that HIWI may play an impotent role in determining or maintaining stemness of these cells. That HIWI expression has been detected in several type tumours may suggest its association with clinical outcome in cancer patients.
  
  
  METHODS
  With the methods of real-time PCR, western blot, immunocytochemistry and immunohistochemistry, the expression of HIWI in three esophageal squamous cancer cell lines KYSE70, KYSE140 and KYSE450 has been characterized. Then, we investigated HIWI expression in a series of 153 esophageal squamous cell carcinomas using immunohistochemistry and explored its association with clinicopathological features.
  
  
  RESULTS
  The expression of HIWI was observed in tumour cell nuclei or/and cytoplasm in 137 (89.5%) cases, 16 (10.5%) cases were negative in both nuclei and cytoplasm. 86 (56.2%) were strongly positive in cytoplasm, while 49 (32.0%) were strongly positive in nuclei. The expression level of HIWI in cytoplasm of esophageal cancer cells was significantly associated with histological grade (P = 0.011), T stage (P = 0.035), and clinic outcome (P < 0.001), while there was no correlation between the nuclear HIWI expression and clinicopathological features.
  
  
  CONCLUSIONS
  The expression of HIWI in the cytoplasm of esophageal cancer cells is significantly associated with higher histological grade, clinical stage and poorer clinical outcome, indicating its possible involvement in cancer development.
authors.affiliation: Department of Oncology, the First Affiliated Hospital of Zhengzhou University, PR China. hewei726@126.com
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Wang
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Fan
authors.forename: Chengcao
authors.initials: C
authors.lastname: Shou
authors.forename: Junsheng
authors.initials: J
authors.lastname: Wang
authors.forename: Karl-Erik
authors.initials: KE
authors.lastname: Giercksky
authors.forename: Jahn M
authors.initials: JM
authors.lastname: Nesland
authors.forename: Zhenhe
authors.initials: Z
authors.lastname: Suo
mesh_terms: D000328:Adult; D000368:Aged; D060565:Argonaute Proteins; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D004938:Esophageal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011506:Proteins / Q000378:metabolism*; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D046888:Tissue Array Analysis
chemical_list: D060565:Argonaute Proteins; D014408:Biomarkers, Tumor; C421088:PIWIL1 protein, human; D011506:Proteins