Large-scale isotype-specific quantification of Serum amyloid A 1/2 by multiple reaction monitoring in crude sera.
Quantification is an essential step in biomarker development. Multiple reaction monitoring (MRM) is a new modified mass spectrometry-based quantification technology that does not require antibody development. Serum amyloid A (SAA) is a positive acute-phase protein identified as a lung cancer biomarker in our previous study. Acute SAA exists in two isoforms with highly similar (92%) amino acid sequences. Until now, studies of SAA have been unable to distinguish between SAA1 and SAA2. To overcome the unavailability of a SAA2-specific antibody, we developed MRM methodology for the verification of SAA1 and SAA2 in clinical crude serum samples from 99 healthy controls and 100 lung adenocarcinoma patients. Differential measurement of SAA1 and SAA2 was made possible for the first time with the developed isotype-specific MRM method. Most healthy control samples had small or no MS/MS peaks of the targeted peptides otherwise, higher peak areas with 10- to 34-fold increase over controls were detected in lung cancer samples. In addition, our SAA1 MRM data demonstrated good agreement with the SAA1 enzyme-linked immunosorbent assay (ELISA) data. Finally, successful quantification of SAA2 in crude serum by MRM, for the first time, shows that SAA2 can be a good biomarker for the detection of lung cancers.
Department of Biochemistry, BK21 and Research Institute for Veterinary Science College of veterinary Medicine, Seoul National University, Seoul and ProtAnBio, Daegu, Republic of Korea.
Hye-Jin
HJ
Sung
Seon-Ae
SA
Jeon
Jung-Mo
JM
Ahn
Kyung-Jo
KJ
Seul
Jin Young
JY
Kim
Ju Yeon
JY
Lee
Jong Shin
JS
Yoo
Soo-Youn
SY
Lee
Hojoong
H
Kim
Je-Yoel
JY
Cho
D000230:Adenocarcinoma / Q000097:blood*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood*; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms / Q000097:blood; D000685:Serum Amyloid A Protein / Q000378:metabolism*
D014408:Biomarkers, Tumor; D020033:Protein Isoforms; C521404:SAA1 protein, human; C083772:SAA2 protein, human; D000685:Serum Amyloid A Protein