Elevated levels of the acute-phase serum amyloid are associated with heightened lung cancer risk.
BACKGROUND
The authors investigated whether early stage lung cancer could be identified by proteomic analyses of plasma.


METHODS
For the first case-control study, plasma samples from 52 patients with lung cancer and from a group of 51 controls were analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. In a second case-control study, a classifier of 4 markers (mass-to-charge ratio, 11,681, 6843, 5607, and 8762) also was tested for validation on plasma from 16 consecutive patients with screen-detected cancer versus 406 healthy individuals. The most relevant marker was identified, and an enzyme-linked immunosorbent assay-based analysis revealed that signal intensity was correlated with concentration.


RESULTS
The classifier had a sensitivity of 94.23% and a specificity of 76.47% in the first study but lost predictive value in the second study. Nevertheless, the 11,681 cluster, which was identified as serum amyloid protein A (SAA), resulted in a multiple logistic regression model that indicated a strong association with lung cancer. When both studies were considered as a together, the odds ratio (OR) for an SAA intensity > or =0.5 was 10.27 (95% confidence interval [CI], 4.64-22.74), whereas an analysis restricted to stage I cancers (TNM classification) revealed an OR of 8.45 (95% CI, 2.76-25.83) for T1 lung cancer and 21.22 (95% CI, 5.62-80.14) for T2 lung cancer.


CONCLUSIONS
SAA levels were predictive of an elevated risk of lung cancer, supporting the general view that inflammation is implicated in lung cancer development.
Cremona
Mattia
M
Department of Experimental Oncology and Laboratory, National Cancer Institute, Milan, Italy.
Calabrò
Elisa
E
Randi
Giorgia
G
De Bortoli
Maida
M
Mondellini
Piera
P
Verri
Carla
C
Sozzi
Gabriella
G
Pierotti
Marco A
MA
La Vecchia
Carlo
C
Pastorino
Ugo
U
Bongarzone
Italia
I
D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000150:complications; D008175:Lung Neoplasms / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012306:Risk; D012680:Sensitivity and Specificity; D000685:Serum Amyloid A Protein / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D014408:Biomarkers, Tumor; D000685:Serum Amyloid A Protein; D002097:C-Reactive Protein