Identification of patients with nasopharyngeal carcinoma by serum protein profiling using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry.

BACKGROUND: As diagnosis of nasopharyngeal carcinoma at an early disease stage is important, we attempted to distinguish between patients with nasopharyngeal carcinoma and noncancer controls by using serum protein profiles.
METHODS: Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry and CM10 protein chip were used to detect the serum proteomic patterns of 65 patients with nasopharyngeal carcinoma before radiotherapy and 93 noncancer controls. Proteomic spectra of serum samples from 50 nasopharyngeal carcinoma patients and 60 noncancer controls were used as a training set. The validity of the classification tree was then challenged with a blind test set which included another 15 patients with nasopharyngeal carcinoma and 33 noncancer controls. Biomarker Wizard 3.01 and Biomarker Pattern 5.01 were used in combination to analyze the data and to develop diagnostic models.
RESULTS: 21 protein peaks were significantly different between nasopharyngeal carcinoma and controls. 4 mass peaks (M4182, M5343, M5913 and M8702 mass/charge ratio) were chosen automatically to construct a classification tree. The classification tree correctly determined 93.8 % (45/48) of the test samples with 93.3 % (14/15) of the nasopharyngeal carcinoma samples and 93.9 % (31/33) of the noncancer samples. Using a combination of serum protein profiles and Epstein-Barr viral capsid antigen immunoglobulin A antibody tests, the diagnostic sensitivity and specificity were increased to 100 and 97 %, respectively.
CONCLUSIONS: Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry could correctly distinguish nasopharyngeal carcinoma from noncancer individuals and showed great potential for the development of a screening test for the detection of nasopharyngeal carcinoma.