Ki-67 and vascular endothelial growth factor expression in intracranial meningiomas in dogs.
BACKGROUND
Tumor proliferation in human intracranial meningiomas can be defined by the reactivity of the monoclonal antibody MIB-1 to the Ki-67 antigen. Vascular endothelial growth factor (VEGF), a pro-angiogenic factor, is a predictive marker for survival of dogs with intracranial meningiomas.


OBJECTIVE
Ki-67 is expressed in canine intracranial meningiomas and is associated with VEGF expression. Ki-67 expression is a prognostic marker for patient outcome.


METHODS
Seventy client-owned dogs with WHO grade I intracranial meningiomas.


METHODS
Retrospective study assessing the degree of immunostaining for Ki-67 by MIB-1 and VEGF expression in intracranial meningioma tissue from dogs. MIB-1 Labeling Index (LI) was calculated with Image J NIH-software. Extent, intensity, and distribution of VEGF-expression was assessed semiquantitatively. Cross tabulations with Fisher's exact tests and nonparametric Spearman's rank correlations were performed to identify associations between VEGF expression and MIB-1 LI. Fifteen dogs underwent postsurgical radiotherapy and were included in survival analysis. The effect of MIB-1 LI on survival was examined by Kaplan-Meier and Cox proportional hazards regression procedures.


RESULTS
Ki-67 staining was positive in 91% (64/70) and VEGF expression was detected in 96% (67/70). There was no significant association between VEGF expression and MIB-1 LI. MIB-1 LI was not associated with survival.


CONCLUSIONS
MIB-1 antibody can be used to document cell proliferation in intracranial meningiomas in dogs, but does not predict outcome. No association between VEGF as a marker of angiogenesis and tumor proliferation was found. Angiogenesis might be a more important predictor of meningioma activity in dogs than is Ki-67.
Matiasek
L A
LA
Centre for Small Animal Studies, Animal Health Trust, Newmarket, UK. lara.matiasek@aht.org.uk
Platt
S R
SR
Adams
V
V
Scase
T J
TJ
Keys
D
D
Miller
J
J
Adamo
F
F
Long
S
S
Matiasek
K
K
D000818:Animals; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D019394:Ki-67 Antigen / Q000235:genetics / Q000378:metabolism*; D008579:Meningioma / Q000662:veterinary*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
D019394:Ki-67 Antigen; D042461:Vascular Endothelial Growth Factor A