title: Distribution and clinical significance of circulating tumor cells in nasopharyngeal carcinoma.
abstract: OBJECTIVE
  Nasopharyngeal carcinoma is one of the leading malignancies with obscure etiology. Circulating tumor cells have been showed to intimately correlate with characteristics in different kinds of cancer. But links between circulating tumor cells and nasopharyngeal carcinoma were still lacking. Therefore, we explored circulating tumor cells' distribution in nasopharyngeal carcinoma and their possible associations with nasopharyngeal carcinoma.
  
  
  METHODS
  Firstly, we found that the positive ratio of circulating tumor cells is extremely high in four stages of nasopharyngeal carcinoma. Meanwhile, positive ratios of mesenchymal circulating tumor cells were higher in early stages of nasopharyngeal carcinoma. Apart from epithelial circulating tumor cells, total, hybrid and mesenchymal circulating tumor cells were correlated with nasopharyngeal carcinoma clinical stage.
  
  
  RESULTS
  Our results showed that hybrid and mesenchymal circulating tumor cells were associated with nasopharyngeal carcinoma metastasis (both distant and lymph node) and smoking. Meanwhile, hybrid circulating tumor cells expressed the highest Epstein-Barr virus proteins and deoxyribonucleic acid in three types of circulating tumor cells. Moreover, we found that Epstein-Barr virus proteins viral-caspid antigen-immunoglobulin A (VCA/IgA) and early antigen-immunoglobulin A (EA/IgA), but not Epstein-Barr virus-deoxyribonucleic acid, had a closed association with nasopharyngeal carcinoma metastasis. However, Epstein-Barr virus hallmarks failed to associate with other nasopharyngeal carcinoma characteristics. Furthermore, we confirmed that matrix metalloproteinase 9 existed in circulating tumor cells and expressed most in mesenchymal circulating tumor cells. In addition, matrix metalloproteinase 9-expressed extent in hybrid circulating tumor cells is somewhat different from epithelial and mesenchymal circulating tumor cells in matrix metalloproteinase 9-positive circulating tumor cells. Nevertheless, matrix metalloproteinase 9 had no relationship with other nasopharyngeal carcinoma characteristics. Finally, our results showed that circulating tumor cells were decreased in patients after therapies.
  
  
  CONCLUSIONS
  Taken together, circulating tumor cells were tightly correlated with nasopharyngeal carcinoma characteristics. In addition, Epstein-Barr virus was associated with nasopharyngeal carcinoma metastasis. Of note, decreased circulating tumor cells indicated a favorable curative effect in nasopharyngeal carcinoma patients.
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi uwjp2@sina.com.
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Si
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Guiping
authors.initials: G
authors.lastname: Lan
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Zhuoxia
authors.initials: Z
authors.lastname: Deng
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Yongli
authors.initials: Y
authors.lastname: Wang
authors.affiliation: SurExam Bio-Tech, Guangzhou Technology Innovation Base, Guangzhou, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Yangda
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Bo
authors.initials: B
authors.lastname: Huang
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Jingjin
authors.initials: J
authors.lastname: Weng
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Xing
authors.initials: X
authors.lastname: Han
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Benjian
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Ying
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Weimin
authors.initials: W
authors.lastname: Xiong
authors.affiliation: Department of Otolaryngology-Head and Neck Oncology, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Nasopharygeal Carcinoma Institute, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi.
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.affiliation: SurExam Bio-Tech, Guangzhou Technology Innovation Base, Guangzhou, P.R. China.
authors.forename: Shiyang
authors.initials: S
authors.lastname: Wu
mesh_terms: D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000032:analysis; D002277:Carcinoma; D020031:Epstein-Barr Virus Infections / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000097:blood* / Q000473:pathology* / Q000821:virology; D009362:Neoplasm Metastasis / Q000473:pathology; D009360:Neoplastic Cells, Circulating / Q000473:pathology*
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral
keywords: CanPatrol™ CTC-enrichment technique; circulating tumor cells; matrix metalloproteinase 9; metastasis; nasopharyngeal carcinoma