Alpha1-antitrypsin precursor in gastric juice is a novel biomarker for gastric cancer and ulcer.
OBJECTIVE
To search for novel disease-specific markers in gastric juice by investigating the protein concentrations and components in gastric juice from patients with various gastroduodenal diseases.


METHODS
Protein concentrations and pH values in fasting gastric juice were examined in 120 healthy subjects and 39 gastric ulcer, 38 duodenal ulcer, and 31 gastric cancer patients. The protein components in gastric juice were studied by two-dimensional PAGE and mass spectrometric analysis.


RESULTS
Protein concentrations in gastric juice of patients with gastric ulcers and gastric cancer were significantly higher than those in healthy subjects (1.06 and 2.61 mg/mL versus 0.48 mg/mL; P=0.001 and P<0.001, respectively), and duodenal ulcer patients had lower gastric juice protein concentrations compared with healthy subjects (0.26 versus 0.48 mg/mL; P<0.05). Gastric hypoacidity and advanced age were independent factors affecting the protein concentrations in gastric juice with odds ratios of 32.9 (95% confidence interval, 11.8-90.9) and 3.2 (95% confidence interval, 1.3-8.3), respectively. Each electrophoresis images of gastric juice could be classified into one of three patterns: basic band, specific band, or nonspecific band. The frequencies of specific band pattern in healthy subjects, gastric ulcer, duodenal ulcer, and gastric cancer patients were 6%, 42%, 6%, and 93%, respectively. Proteomic analysis revealed that alpha1-antitrypsin precursor was the principal peptide in the specific band.


CONCLUSIONS
alpha1-antitrypsin precursor in gastric juice is a novel biomarker for gastric cancer and ulcer. A noninvasive method to obtain gastric juice followed by proteomic analysis may serve as a new tool to screen for gastric malignancies.
Hsu
Ping-I
PI
Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Veterans General Hospital and National Yang-Ming University, Taiwan.
Chen
Chung-Hsuan
CH
Hsieh
Chieu-Shia
CS
Chang
Wei-Chao
WC
Lai
Kwok-Hung
KH
Lo
Gin-Ho
GH
Hsu
Ping-Ning
PN
Tsay
Feng-Woei
FW
Chen
Yu-Shan
YS
Hsiao
Michael
M
Chen
Hui-Chun
HC
Lu
Pei-Jung
PJ
D000328:Adult; D014408:Biomarkers, Tumor; D004381:Duodenal Ulcer / Q000175:diagnosis / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D005750:Gastric Juice / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008875:Middle Aged; D016017:Odds Ratio; D010455:Peptides / Q000737:chemistry; D011498:Protein Precursors / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology; D014456:Ulcer / Q000378:metabolism*; D000515:alpha 1-Antitrypsin / Q000096:biosynthesis*
D014408:Biomarkers, Tumor; D010455:Peptides; D011498:Protein Precursors; D000515:alpha 1-Antitrypsin; D014357:Trypsin