Identification of biomarkers of human pancreatic adenocarcinomas by expression profiling and validation with gene expression analysis in endoscopic ultrasound-guided fine needle aspiration samples.
OBJECTIVE
To compare gene expression profiles of pancreatic adenocarcinoma tissue specimens, human pancreatic and colon adenocarcinoma and leukemia cell lines and normal pancreas samples in order to distinguish differentially expressed genes and to validate the differential expression of a subset of genes by quantitative real-time RT-PCR (RT-QPCR) in endoscopic ultrasound-guided fine needle aspiration (EUS-guided FNA) specimens.


METHODS
Commercially dedicated cancer cDNA macroarrays (Atlas Human Cancer 1.2) containing 1176 genes were used. Different statistical approaches (hierarchical clustering, principal component analysis (PCA) and SAM) were used to analyze the expression data. RT-QPCR and immunohistochemical studies were used for validation of results.


RESULTS
RT-QPCR validated the increased expression of LCN2 (lipocalin 2) and for the first time PLAT (tissue-type plasminogen activator or tPA) in malignant pancreas as compared with normal pancreas. Immunohistochemical analysis confirmed the increased expression of LCN2 protein localized in epithelial cells of ducts invaded by carcinoma. The analysis of PLAT and LCN2 transcripts in 12 samples obtained through EUS-guided FNA from patients with pancreatic adenocarcinoma showed significantly increased expression levels in comparison with those found in normal tissues, indicating that a sufficient amount of high quality RNA can be obtained with this technique.


CONCLUSIONS
Expression profiling is a useful method to identify biomarkers and potential target genes. Molecular analysis of EUS-guided FNA samples in pancreatic cancer appears as a valuable strategy for the diagnosis of pancreatic adenocarcinomas.
Laurell
Henrik
H
INSERM U531, IFR31, Institut Louis Bugnard, Toulouse, France.
Bouisson
Michele
M
Berthelemy
Philippe
P
Rochaix
Philippe
P
Dejean
Sebastien
S
Besse
Philippe
P
Susini
Christiane
C
Pradayrol
Lucien
L
Vaysse
Nicole
N
Buscail
Louis
L
D000209:Acute-Phase Proteins / Q000032:analysis / Q000235:genetics; D000230:Adenocarcinoma / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000235:genetics*; D044963:Biopsy, Fine-Needle / Q000379:methods; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology; D019160:Endosonography / Q000379:methods; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D052138:Genes, Neoplasm / Q000235:genetics; D006801:Humans; D053552:Keratin-7; D007633:Keratins / Q000032:analysis / Q000235:genetics; D007938:Leukemia / Q000235:genetics / Q000473:pathology; D000071068:Lipocalin-2; D054834:Lipocalins; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D010959:Tissue Plasminogen Activator / Q000032:analysis / Q000235:genetics
D000209:Acute-Phase Proteins; D014408:Biomarkers, Tumor; C507497:KRT7 protein, human; D053552:Keratin-7; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D007633:Keratins; C067262:PLAT protein, human; D010959:Tissue Plasminogen Activator