title: The significance and robustness of a plasma free amino acid (PFAA) profile-based multiplex function for detecting lung cancer.
abstract: BACKGROUND
  We have recently reported on the changes in plasma free amino acid (PFAA) profiles in lung cancer patients and the efficacy of a PFAA-based, multivariate discrimination index for the early detection of lung cancer. In this study, we aimed to verify the usefulness and robustness of PFAA profiling for detecting lung cancer using new test samples.
  
  
  METHODS
  Plasma samples were collected from 171 lung cancer patients and 3849 controls without apparent cancer. PFAA levels were measured by high-performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS).
  
  
  RESULTS
  High reproducibility was observed for both the change in the PFAA profiles in the lung cancer patients and the discriminating performance for lung cancer patients compared to previously reported results. Furthermore, multivariate discriminating functions obtained in previous studies clearly distinguished the lung cancer patients from the controls based on the area under the receiver-operator characteristics curve (AUC of ROC = 0.731 ~ 0.806), strongly suggesting the robustness of the methodology for clinical use. Moreover, the results suggested that the combinatorial use of this classifier and tumor markers improves the clinical performance of tumor markers.
  
  
  CONCLUSIONS
  These findings suggest that PFAA profiling, which involves a relatively simple plasma assay and imposes a low physical burden on subjects, has great potential for improving early detection of lung cancer.
authors: Division of Thoracic Diseases, Chiba Cancer Center, 666-2, Nitona-cho, Chuo-ku, Chiba 260-8717, Japan. mshingyoji@chiba-cc.jp
authors: Masato
authors: M
authors: Shingyoji
authors: Toshihiko
authors: T
authors: Iizasa
authors: Masahiko
authors: M
authors: Higashiyama
authors: Fumio
authors: F
authors: Imamura
authors: Nobuhiro
authors: N
authors: Saruki
authors: Akira
authors: A
authors: Imaizumi
authors: Hiroshi
authors: H
authors: Yamamoto
authors: Takashi
authors: T
authors: Daimon
authors: Osamu
authors: O
authors: Tochikubo
authors: Toru
authors: T
authors: Mitsushima
authors: Minoru
authors: M
authors: Yamakado
authors: Hideki
authors: H
authors: Kimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000596:Amino Acids / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D055088:Early Detection of Cancer / Q000379:methods; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D055815:Young Adult
chemical_list: D000596:Amino Acids; D014408:Biomarkers, Tumor