Application of a global proteomic approach to archival precursor lesions: deleted in malignant brain tumors 1 and tissue transglutaminase 2 are upregulated in pancreatic cancer precursors.
BACKGROUND
Pancreatic cancer is an almost uniformly fatal disease, and early detection is a critical determinant of improved survival. A variety of noninvasive precursor lesions of pancreatic adenocarcinoma have been identified, which provide a unique opportunity for intervention prior to onset of invasive cancer. Biomarker discovery in precursor lesions has been hampered by the ready availability of fresh specimens, and limited yields of proteins suitable for large scale screening.


METHODS
We utilized Liquid Tissue, a novel technique for protein extraction from archival formalin-fixed material, and mass spectrometry to conduct a global proteomic analysis of an intraductal papillary mucinous neoplasm (IPMN). Tissue microarrays comprised of 38 IPMNs were used for validation of candidate proteins.


RESULTS
The proteomic analysis of the IPMN Liquid Tissue lysate resulted in identification of 1,534 peptides corresponding to 523 unique proteins. A subset of 25 proteins was identified that had previously been reported as upregulated in pancreatic cancer. Immunohistochemical analysis for two of these, deleted in malignant brain tumors 1 (DMBT1) and tissue transglutaminase 2 (TGM2), confirmed their overexpression in IPMNs.


CONCLUSIONS
Global proteomics analysis using the Liquid Tissue workflow is a feasible approach for unbiased biomarker discovery in limited archival material, particularly applicable to precursor lesions of cancer.
Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
Wang
W
Cheung
Marlene M
MM
Darfler
Hector
H
Alvarez
Brian L
BL
Hood
Thomas P
TP
Conrads
Nils
N
Habbe
David B
DB
Krizman
Jan
J
Mollenhauer
Georg
G
Feldmann
Anirban
A
Maitra
D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D019204:GTP-Binding Proteins; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D011230:Precancerous Conditions / Q000235:genetics / Q000378:metabolism*; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D013048:Specimen Handling; D011503:Transglutaminases / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D015854:Up-Regulation
D002135:Calcium-Binding Proteins; C108174:DMBT1 protein, human; D004268:DNA-Binding Proteins; D011956:Receptors, Cell Surface; C000717608:TGM2 protein, human; D025521:Tumor Suppressor Proteins; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins