Gastric cancer-specific protein profile identified using endoscopic biopsy samples via MALDI mass spectrometry.
To date, proteomic analyses on gastrointestinal cancer tissue samples have been performed using surgical specimens only, which are obtained after a diagnosis is made. To determine if a proteomic signature obtained from endoscopic biopsy samples could be found to assist with diagnosis, frozen endoscopic biopsy samples collected from 63 gastric cancer patients and 43 healthy volunteers were analyzed using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. A statistical classification model was developed to distinguish tumor from normal tissues using half the samples and validated with the other half. A protein profile was discovered consisting of 73 signals that could classify 32 cancer and 22 normal samples in the validation set with high predictive values (positive and negative predictive values for cancer, 96.8% and 91.3%; sensitivity, 93.8%; specificity, 95.5%). Signals overexpressed in tumors were identified as alpha-defensin-1, alpha-defensin-2, calgranulin A, and calgranulin B. A protein profile was also found to distinguish pathologic stage Ia (pT1N0M0) samples (n = 10) from more advanced stage (Ib or higher) tumors (n = 48). Thus, protein profiles obtained from endoscopic biopsy samples may be useful in assisting with the diagnosis of gastric cancer and, possibly, in identifying early stage disease.
Kim
Hark Kyun
HK
Laboratory of Cancer Biology and Genetics, National Cancer Institute, Bethesda, Maryland 20892, USA.
Reyzer
Michelle L
ML
Choi
Il Ju
IJ
Kim
Chan Gyoo
CG
Kim
Hee Sung
HS
Oshima
Akira
A
Chertov
Oleg
O
Colantonio
Simona
S
Fisher
Robert J
RJ
Allen
Jamie L
JL
Caprioli
Richard M
RM
Green
Jeffrey E
JE
D014408:Biomarkers, Tumor / Q000032:analysis*; D001706:Biopsy; D016022:Case-Control Studies; D023082:Defensins / Q000378:metabolism; D005773:Gastroscopy / Q000379:methods; D006801:Humans; D039841:Leukocyte L1 Antigen Complex / Q000378:metabolism; D015233:Models, Statistical; D040901:Proteomics / Q000379:methods*; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000378:metabolism* / Q000473:pathology
D014408:Biomarkers, Tumor; D023082:Defensins; D039841:Leukocyte L1 Antigen Complex