An autoantibody-mediated immune response to calreticulin isoforms in pancreatic cancer.
The identification of circulating tumor antigens or their related autoantibodies provides a means for early cancer diagnosis as well as leads for therapy. We have used a proteomic approach to identify proteins that commonly induce a humoral response in pancreatic cancer. Aliquots of solubilized proteins from a pancreatic cancer cell line (Panc-1) were subjected to two-dimensional PAGE, followed by Western blot analysis in which sera of individual patients were tested for primary antibodies. Sera from 36 newly diagnosed patients with pancreatic cancer, 18 patients with chronic pancreatitis, 33 patients with other cancers, and 15 healthy subjects were analyzed. Autoantibodies were detected against either one or two calreticulin isoforms identified by mass spectrometry in sera from 21 of 36 patients with pancreatic cancer. One of 18 chronic pancreatitis patients and 1 of 15 healthy controls demonstrated autoantibodies to calreticulin isoform 1; none demonstrated autoantibodies to isoform 2. None of the sera from patients with colon cancer exhibited reactivity against either of these two proteins. One of 14 sera from lung adenocarcinoma patients demonstrated autoantibodies to calreticulin isoform 1; 2 of 14 demonstrated autoantibodies to isoform 2. Immunohistochemical analysis of calreticulin in pancreatic/ampullary tumor tissue arrays using an isoform nonspecific antibody revealed diffuse and consistent cytoplasmic staining in the neoplastic epithelial cells of the pancreatic and ampullary adenocarcinomas. The detection of autoantibodies to calreticulin isoforms may have utility for the early diagnosis of pancreatic cancer.
Department of Pediatrics, University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0656, USA.
Su-Hyung
SH
Hong
David E
DE
Misek
Hong
H
Wang
Eric
E
Puravs
Thomas J
TJ
Giordano
Joel K
JK
Greenson
Dean E
DE
Brenner
Diane M
DM
Simeone
Craig D
CD
Logsdon
Samir M
SM
Hanash
D000230:Adenocarcinoma / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000368:Aged; D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D001323:Autoantibodies / Q000276:immunology* / Q000378:metabolism; D015153:Blotting, Western; D037282:Calreticulin / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D002908:Chronic Disease; D003110:Colonic Neoplasms / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D003593:Cytoplasm; D015180:Electrophoresis, Gel, Two-Dimensional; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D020869:Gene Expression Profiling; D006031:Glycosylation; D006801:Humans; D013058:Mass Spectrometry; D008875:Middle Aged; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D010195:Pancreatitis / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D020033:Protein Isoforms; D040901:Proteomics
D000951:Antigens, Neoplasm; D001323:Autoantibodies; D037282:Calreticulin; D020033:Protein Isoforms