vegf expression in hrf
Post on 16-Jul-2015
101 Views
Preview:
TRANSCRIPT
Background
Retinoblastoma(Rb)
Rapidly developing
cancer of the retina
Most common in children
Mutation in chromosome
13 in RB1
Invasive Retinoblastoma
represents the real
challenge in clinics
Background:
Angiogenesis
Angiogenesis is essential for tumor growth and metastasis
Pathological retinal angiogenesis occurs in several diseases characterized by retinal ischemia
Angiogenesis may complicate the clinical presentation by inducing glaucoma due to iris neovascularization(NVI) with secondary peripheral synechiae(PAS) formation
Inhibion of angiogenesis has been shown to kill retinoblastoma cells (harbour ophtalmic research)
Avastin (anti VEGF antibody)
Tyrosine kinase inhibitors
VEGF inhibition may also help as a chemosensityzer
Background: VEGF
VEGF is a hypoxia inducible
cytokine required for retinal
vascularization
Produced by Rb tumor
There are several pro-
angiogenic factors involved
in retinal angiogenesis
VEGF and its receptors are
expresed in non-
overlapping manner
(Prospero Ponce et al 2013)
•Choroidal invasion
(‹3mm) + ANY optic
nerve involvement
High Risk Features
RPE
Choroid
Retina
Optic Nerve
involvement
Choroidal
involvement
Angiogenesis complicates RB
Neovascularization of the iris (NVI)
+/-
Peripheral synechia (PAS)
Neovascular Glaucoma
Relevant background
Neovascularization in retinoblastoma is associated with poorer prognosis and increased chances of invasion
Neovascularization as well as angiogenesis is driven by angiogenic factors.
VEGF is the most important and most studied angiogenic factor
Several anti-VEGF therapies have demonstrated good results in various types of cancer
No one has studied histopathological behavior of VEGF in Rb
VEGF is a promising therapy in Retinoblastoma
Objective
To analyze the expression of angiogenic factors in
the eye (retina, iris, and tumor ) in
retinoblastoma with high-risk features (HRF) and
non-high risk features (Non-HRF). To correlate the
expression of angiogenic factors in tumors with HRF and the expression of stem cell marker
Sox2. keep order same throughout. If possible,
use this order when discussing your results as well.
Methods
AngiogenicFactors
•VEGF
•VEGFR2
•CD105 (endoglin)
Differentiation Factors
•Vimentin
•GFAP
Immuno-histochemistry
•Double Stain
Qualitative measure
•Grade 0 to 3
Quantitative measure
•Image J
•Total area
Differentiation Factors
Vimentin
Intermediate filament
associated with fibroblasts
and activated Muller cells
It can also be expressed
by RPE, cilliary body
epithelium, lens epithelium
GCL
INL
ONL
Differentiation Factors
Glial fibrillary acidic protein
(GFAP)
Normal retinaDamaged retina
•Intermediate
filament
•Associated to:
glial cells- Muller
cells
Up-regulated in
CNS and retinal
injury
Color deconvolution
Stain separation using Ruifrok and Johnston's method1
Measurements: Image J
[1] Ruifrok AC, Johnston DA. Quantification of histochemical staining by color deconvolution. Anal Quant Cytol Histol 23: 291-299, 2001
Vimentin VEGF
A B C
D E F
100 μm100 μm100 μm
VEGF
Ret
ina
Tumor
Iris
0
2000
4000
6000
8000HRF
NON-HRF
p<0.05
Location
Pix
el
Are
a
Vimentin
Ret
ina
Tumor
Iris
0
5000
10000
15000
20000HRF
Non-HRF
p<0.05
Location
Pix
el
Are
a
VEGF+ Vimentin
Ret
ina
Tumor
Iris
0
2000
4000
6000
8000HRF
Non-HRFp<0.05
LocationP
ixel
Are
a
*
Figure 1.
A B C
D E F
100 μm
GFAP
HRF
Non-H
RF
0
1000
2000
3000
4000
5000
Tumor Type
Pix
el
Are
a
VEGF
HRF
Non-H
RF
0
1000
2000
3000
4000
5000
Tumor Type
Pix
el
Are
a
VEGF+GFAP
HRF
Non-H
RF
0
200
400
600
800
1000
Tumor TypeP
ixel
Are
a
**
Figure 2.
A B C
D E F
100 μm
VEGFR2
Ret
ina
Tumor
Iris
0
1000
2000
3000HRF
Non-HRFp<0.05
Location
Pix
el
Are
a
CD105
Ret
ina
Tumor
Iris
0
500
1000
1500HRF
Non-HRFp<0.05
Location
Pix
el
Are
a
VEGFR2 + CD105
Ret
ina
Tumor
Iris
0
50
100
150
200
250HRF
Non-HRF
Pix
el
Are
a
Figure 3.
*
*
*
*
*
TR
Summary
HRF tumor s express more VEGF and VEGFR2 than
non-HRF
Comparison with other stainings indicate that
VEGF secretion might be done by tumor cells
Neovascularization occures more in the iris
This expression is correlated with the expression of
stem cell marker SOX2
Conclusions
HRF tumors seem to be more “stem like”
They might regulate their invasiveness through a
VEGF feedback loop
Temporal expression of VEGF receptors should be
considered
Anti-VEGF therapy might be a promising therapy
for Rb and its side effects
top related