|
|
Microvessel density
predicts behavior in pediatric optic pathway/hypothalamic gliomas
U. K. Bartels, C. Hawkins, J. Ma, A. Ray, P. Dirks, J. Rutka, E. Bouffet
The Hospital for Sick Children, Toronto, ON, Canada
Background.
Optic pathway/hypothalamic gliomas (OPHG) are predominately
low-grade tumors.
However, OPHGs show an unpredictable behavior and there is no recognized
histologic or molecular marker anticipating this behavior.
This study was performed to investigate angiogenic features as possible
independent prognostic factors.
Methods.
We searched the databases of the Hospital for Sick Children for
patients with pathologically diagnosed OPHGs between 1985 and 2002.
Tumor specimens were reviewed and reconfirmed as low-grade gliomas.
Those with sufficient tissue for staining were included in the study.
Sections were immunostained with factor VIII (F8) and counted for microvessel
density (MD).
A ratio of alpha-smooth muscle actin to F8 immunostaining was calculated to give
a vascular maturity index.
Vascular endothelial growth factor (VEGF) and VEGF-receptor immunostaining was
performed to assess angiogenic features and MIB-1 labeling index (LI) to assess
proliferation.
These factors were evaluated with respect to progression-free survival (PFS) and
outcome of treatment.
Results.
60 patients were identified and 41 had sufficient material for
further analysis.
All patients underwent surgery.
30 required additional treatment (16 chemotherapy, 8 radiation, 6 chemotherapy +
radiation).
8 patients had NF1.
38 are alive.
MD showed a wide range of variation between tumors (4.8-73.6, median: 28
vessels/1.2 mm2).
The absolute number of F8 stained vessels was significantly higher in infants (p
< 0.01).
A high MD (> 20 vessels/1.2mm2) was associated with a significantly shorter
PFS compared to tumors with a low MD (<20 vessels/1.2 mm2)(p=0.025).
MIB-1 values ranged from 0-10 (median 2.5).
Intensity and distribution of VEGF and VEGFR staining and MIB-1 LI were not
significantly associated with outcome.
Conclusions.
Our findings suggest that angiogenesis is important in
low-grade glioma and MD rather than MIB-1 has a prognostic value in OPHGs.
Copyright 2004 American Society of Clinical Oncology All rights
reserved worldwide.
Source: http://www.asco.org/ac/1,1003,_12-002636-00_18-0026-00_19-004305,00.asp
|
