title: Identification of serum amyloid a protein as a potentially useful biomarker to monitor relapse of nasopharyngeal cancer by serum proteomic profiling.
abstract: OBJECTIVE
  Nasopharyngeal cancer (NPC) is a common cancer in Hong Kong, and relapse can occur frequently. Using protein chip profiling analysis, we aimed to identify serum biomarkers that were useful in the diagnosis of relapse in NPC.
  
  
  METHODS
  Profiling analysis was performed on 704 sera collected from 42 NPC patients, 39 lung cancer patients, 30 patients with the benign metabolic disorder thyrotoxicosis (TX), and 35 normal individuals (NM). Protein profile in each NPC patient during clinical follow up was correlated with the relapse status.
  
  
  RESULTS
  Profiling analysis identified two biomarkers with molecular masses of 11.6 and 11.8 kDa, which were significantly elevated in 22 of 31 (71%) and 21 of 31 (68%) NPC patients, respectively, at the time of relapse (RP) as compared with 11 patients in complete remission (CR; RP versus CR, P = 0.009), 30 TX (RP versus TX, P < 0.001), or 35 NM (RP versus NM, P < 0.001). The markers were also elevated in 16 of 39 (41%) lung cancer patients at initial diagnosis. By tryptic digestion, followed by tandem mass spectrometry fragmentation, the markers were identified as two isoforms of serum amyloid A (SAA) protein. Monitoring the patients longitudinally for SAA level both by protein chip and immunoassay showed a dramatic SAA increase, which correlated with relapse and a drastic fall correlated with response to salvage chemotherapy. Serum SAA findings were compared with those of serum Epstein-Barr virus DNA in three relapsed patients showing a similar correlation with relapse and chemo-response.
  
  
  CONCLUSIONS
  SAA could be a useful biomarker to monitor relapse of NPC.
authors.affiliation: Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong Special Administrative Region, The People's Republic of China.
authors.forename: William C S
authors.initials: WC
authors.lastname: Cho
authors.forename: Timothy T C
authors.initials: TT
authors.lastname: Yip
authors.forename: Christine
authors.initials: C
authors.lastname: Yip
authors.forename: Victor
authors.initials: V
authors.lastname: Yip
authors.forename: Vanitha
authors.initials: V
authors.lastname: Thulasiraman
authors.forename: Roger K C
authors.initials: RK
authors.lastname: Ngan
authors.forename: Tai-Tung
authors.initials: TT
authors.lastname: Yip
authors.forename: Wai-Hon
authors.initials: WH
authors.lastname: Lau
authors.forename: Joseph S K
authors.initials: JS
authors.lastname: Au
authors.forename: Stephen C K
authors.initials: SC
authors.lastname: Law
authors.forename: Wai-Wai
authors.initials: WW
authors.lastname: Cheng
authors.forename: Victor W S
authors.initials: VW
authors.lastname: Ma
authors.forename: Cadmon K P
authors.initials: CK
authors.lastname: Lim
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood*; D004279:DNA, Viral / Q000097:blood; D020031:Epstein-Barr Virus Infections / Q000821:virology; D005260:Female; D005500:Follow-Up Studies; D004854:Herpesvirus 4, Human / Q000235:genetics; D006723:Hong Kong; D006801:Humans; D008137:Longitudinal Studies; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008175:Lung Neoplasms / Q000097:blood / Q000556:secondary / Q000821:virology; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000097:blood* / Q000556:secondary / Q000821:virology; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000175:diagnosis* / Q000821:virology; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D020543:Proteome; D040901:Proteomics; D012074:Remission Induction; D000685:Serum Amyloid A Protein / Q000378:metabolism*; D013971:Thyrotoxicosis / Q000097:blood / Q000821:virology
chemical_list: D014408:Biomarkers, Tumor; D004279:DNA, Viral; D020543:Proteome; D000685:Serum Amyloid A Protein