Oral cancer plasma tumor marker identified with bead-based affinity-fractionated proteomic technology.
BACKGROUND
There is no plasma marker for detecting oral cancer, one of the most frequent cancers worldwide. We developed a bead-based affinity-fractionated proteomic method to discover a novel plasma marker for oral cancer.


METHODS
Affinity purification of heparinized plasma with magnetic beads and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis were used to screen potential oral cancer markers. We compiled MS protein profiles for 57 patients with oral cancer and compared them with profiles from 29 healthy controls. The spectra were analyzed statistically using flexAnalysis and ClinProt bioinformatic software. In each MS analysis, the peak intensities of interest were normalized with an internal standard (adrenocorticotropic hormone 18-39). For identification, affinity bead-purified plasma protein was subjected to MALDI TOF/TOF analysis followed by Mascot identification of the peptide sequences and a search of the National Center for Biotechnology Information protein database.


RESULTS
To optimize MALDI-TOF analysis based on the best discriminator of the cancer and control spectra, copper-chelated beads were used for plasma protein profiling. The within- and between-run CVs for assays were <4% and 7%, respectively. Six markers that differentiated between cancer and control spectra were found, with mean (SD) molecular masses of 2664 (1), 2850 (1), 3250 (1), 7735 (2), 7927 (2), and 9240 (2) Da. The 2664-Da marker, identified as a fragment of the fibrinogen alpha-chain, had the highest sensitivity (100%) and specificity (97%) for cancer.


CONCLUSIONS
The high specificity and sensitivity of the fibrinogen alpha-chain fragment suggest that it may be a clinical useful tumor marker.
Cheng
Ann-Joy
AJ
Department of Medical Biotechnology, Chang Gung University, Taoyuan, Taiwan. ajchen@mail.cgu.edu.tw
Chen
Li-Chiu
LC
Chien
Kun-Yi
KY
Chen
Yin-Ju
YJ
Chang
Joseph Tung-Chieh
JT
Wang
Hung-Ming
HM
Liao
Chun-Ta
CT
Chen
I-How
IH
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D003300:Copper; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000097:blood*; D040081:Protein Array Analysis / Q000295:instrumentation / Q000379:methods; D040901:Proteomics / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D003300:Copper