Distinctive serum protein profiles involving abundant proteins in lung cancer patients based upon antibody microarray analysis.
BACKGROUND
Cancer serum protein profiling by mass spectrometry has uncovered mass profiles that are potentially diagnostic for several common types of cancer. However, direct mass spectrometric profiling has a limited dynamic range and difficulties in providing the identification of the distinctive proteins. We hypothesized that distinctive profiles may result from the differential expression of relatively abundant serum proteins associated with the host response.


METHODS
Eighty-four antibodies, targeting a wide range of serum proteins, were spotted onto nitrocellulose-coated microscope slides. The abundances of the corresponding proteins were measured in 80 serum samples, from 24 newly diagnosed subjects with lung cancer, 24 healthy controls, and 32 subjects with chronic obstructive pulmonary disease (COPD). Two-color rolling-circle amplification was used to measure protein abundance.


RESULTS
Seven of the 84 antibodies gave a significant difference (p < 0.01) for the lung cancer patients as compared to healthy controls, as well as compared to COPD patients. Proteins that exhibited higher abundances in the lung cancer samples relative to the control samples included C-reactive protein (CRP; a 13.3 fold increase), serum amyloid A (SAA; a 2.0 fold increase), mucin 1 and alpha-1-antitrypsin (1.4 fold increases). The increased expression levels of CRP and SAA were validated by Western blot analysis. Leave-one-out cross-validation was used to construct Diagonal Linear Discriminant Analysis (DLDA) classifiers. At a cutoff where all 56 of the non-tumor samples were correctly classified, 15/24 lung tumor patient sera were correctly classified.


CONCLUSIONS
Our results suggest that a distinctive serum protein profile involving abundant proteins may be observed in lung cancer patients relative to healthy subjects or patients with chronic disease and may have utility as part of strategies for detecting lung cancer.
Gao
Wei-Min
WM
Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA. gaow@upmc.edu
Kuick
Rork
R
Orchekowski
Randal P
RP
Misek
David E
DE
Qiu
Ji
J
Greenberg
Alissa K
AK
Rom
William N
WN
Brenner
Dean E
DE
Omenn
Gilbert S
GS
Haab
Brian B
BB
Hanash
Samir M
SM
D000906:Antibodies / Q000737:chemistry; D000912:Antibodies, Neoplasm / Q000737:chemistry; D001798:Blood Proteins / Q000737:chemistry* / Q000378:metabolism; D015153:Blotting, Western; D002097:C-Reactive Protein / Q000096:biosynthesis; D016022:Case-Control Studies; D003101:Collodion / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods; D046228:Microarray Analysis / Q000379:methods; D009077:Mucins / Q000096:biosynthesis; D040081:Protein Array Analysis / Q000379:methods*; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism; D000685:Serum Amyloid A Protein / Q000096:biosynthesis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000515:alpha 1-Antitrypsin / Q000096:biosynthesis
D000906:Antibodies; D000912:Antibodies, Neoplasm; D001798:Blood Proteins; D009077:Mucins; D000685:Serum Amyloid A Protein; D000515:alpha 1-Antitrypsin; D003101:Collodion; D002097:C-Reactive Protein