title: Osteopontin expression in nasopharyngeal carcinoma: its relevance to the clinical stage of the disease.
abstract: OBJECTIVE
  To investigate osteopontin (OPN) expression in human nasopharyngeal carcinoma (NPC) and evaluate its clinical significance in the disease.
  
  
  METHODS
  The expression of OPN mRNA in 44 frozen NPC tissue and 15 normal nasopharyngeal epithelium tissue (NNET) samples was examined by semi-quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). OPN protein expression in 67 paraffin-embedded NPC tissue and 21 NNET samples was detected by immunohistochemistry (IHC). In addition, OPN expression was investigated in 12 paired NPC and para-carcinoma tissue (PCT) samples by western blotting (WB). The association between the expression of OPN and the clinicopathologic parameters of NPC was evaluated.
  
  
  RESULTS
  Three different methods all showed that the expression of OPN mRNA or protein in NPC was significantly higher than in NNET or PCT (P = 0.000, 0.001, 0.000, respectively). After an examination by IHC, 88.1% (59/67) of NPC samples showed strong or moderate positive OPN staining and 28.6% (6/21) of NNET samples displayed a weak positive OPN staining. The staining of OPN in tumor cells was mainly localized to the cytoplasm. OPN expression in NPC was not related to patient age or sex (P > 0.05), but was significantly related to tumor size, regional lymph nodal metastasis, and NPC clinical stages (P < 0.05).
  
  
  CONCLUSIONS
  Our study demonstrated that OPN mRNA and protein overexpression in NPC may be important in the pathogenesis of the disease. It was strongly related to T stage, N stage and clinical stages of NPC, suggesting that OPN may be involved in NPC metastasis and progression.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xiangya Hospital, Central-South University, Changsha City, Hunan Province, China.
authors.forename: Hong-Han
authors.initials: HH
authors.lastname: Wang
authors.forename: Xing-Wei
authors.initials: XW
authors.lastname: Wang
authors.forename: Can-E
authors.initials: CE
authors.lastname: Tang
mesh_terms: D000328:Adult; D002277:Carcinoma; D016022:Case-Control Studies; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D009367:Neoplasm Staging; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism*; D018709:Statistics, Nonparametric
chemical_list: D053495:Osteopontin