Vascular endothelial growth factor, FLT-1, and FLK-1 analysis in a pancreatic cancer tissue microarray.
BACKGROUND
Measures of vascular endothelial growth factor (VEGF) expression in pancreatic cancer typically have been qualitative or semiquantitative. The objective of this study was to use a series of algorithms called AQUA that quantitatively assesses protein expression on tissue microarrays (TMAs) to compare in situ expression of VEGF and its primary receptors, VEGF receptor 1 (FLT-1) and VEGF receptor 1 (FLK-1), on a pancreatic cancer TMA.


METHODS
TMAs were constructed by arraying 1.5-mm cores from 76 samples of pancreatic adenocarcinoma (1996-2002) that were obtained from the archives of the Yale Department of Pathology. The staining for AQUA was similar to standard immunohistochemistry and involved antigen retrieval and the application of primary antibodies, but with epifluorescence detection. Slides were counterstained with 4',6-diamidino-2-phenylindole for nuclear visualization and cytokeratin for membrane visualization. The primary antibodies used were VEGF, FLT-1, FLK-1, and cytokeratin.


RESULTS
Disease stage was highly prognostic for outcome, as expected. Total amounts of VEGF and its receptors were assessed within the tumor mask and were divided into quartiles. Kaplan-Meier survival curves showed that VEGF and FLK-1 were not associated clearly with outcome. However, the expression of FLT-1 was correlated significantly, and the patients who had tumors with the lowest expression FLT-1 levels had the worst survival (P = .0038). In multivariate analysis, FLT-1 expression was an independent prognostic factor for overall survival (P = .0044).


CONCLUSIONS
VEGF and its 2 principal receptors were expressed to varying degrees in tumors of the pancreas. A significant association was found between low expression of FLT-1 and both poor prognosis and advanced stage, suggesting that tumor expression of this VEGF receptor is a marker of less aggressive disease.
Chung
Gina G
GG
Yale Cancer Center and Department of Internal Medicine, Section of Medical Oncology, Yale University School of Medicine, New Haven, Connecticut 06520, USA. gina.chung@yale.edu
Yoon
Harry H
HH
Zerkowski
Maciej P
MP
Ghosh
Sriparna
S
Thomas
Laurie
L
Harigopal
Malini
M
Charette
Lori A
LA
Salem
Ronald R
RR
Camp
Robert L
RL
Rimm
David L
DL
Burtness
Barbara A
BA
D000230:Adenocarcinoma / Q000737:chemistry* / Q000401:mortality / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000737:chemistry* / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D015996:Survival Rate; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000032:analysis*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000032:analysis*
D042461:Vascular Endothelial Growth Factor A; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2