UCSF Hyperpolarized MR Seminar Summer 2019, Lecture #8-1 "Integration into Biomedical Research - Cancer" Lecturer: Pavithra Viswanath Sponsored by the NIH/NIBIB-supported UCSF Hyperpolarized MRI Technology Resource Center (P41EB013598) https://radiology.ucsf.edu/research/labs/hyperpolarized-mri-tech

1. Integration of Hyperpolarized
MR Into Biomedical Research-
Cancer
BioE 297
8/22/19
Pavithra Viswanath
Ronen Lab

2. Learning Objectives
• Understand the paradigm of cancer as a genetic and metabolic disease
• metabolic reprogramming in cancer
• Learn about the various ways in which altered metabolism can be used
to non-invasively monitor tumor burden and response to therapy
• Focus on brain tumors
• Focus on relatively new technologies with clinical translation

3. Cancer is a genetic disease
• Tumorigenesis involves the
accumulation of genetic and
epigenetic alterations that allow cells
to
• proliferate indefinitely
• avoid immune destruction
• invade surrounding tissue
• Most cancers arise from acquired
somatic mutations in
• tumor suppressor genes (e.g. p53)
• proto-oncogenes (e.g. Ras or
Myc)

4. Gliomas are a significant clinical problem
• Brain tumors are among the most feared
of all forms of cancer.
• Long-term cognitive and physical deficits
• More than two-thirds of adults
diagnosed with glioblastoma -the most
aggressive type of brain cancer- will die
within 2 years of diagnosis.
• Brain tumors are also the most common
and most lethal of all pediatric solid
tumors.
1.4 million
worldwide

5. Gliomas are a significant clinical problem
Brain

6. Gliomas have traditionally been classified by histology
WHO grading:
Grade I: Low-proliferative potential
Grade II: Mild increase in cell number
Grade III: Mitotic activity, infiltrative, anaplastic
Grade IV: High mitosis, necrosis and rapid progression- High-grade glioblastoma
Low-grade gliomas

7. Gliomas are now classified by their genetics
Histologically similar
gliomas have very
different genetic
profiles- different
diseases!
High-grade glioblastoma
Low-grade glioma
Low-grade glioma

8. Gliomas are now classified by their genetics
indicates metabolic
regulator
Genomics Metabolism

9. Many of the oncogenic events in gliomas alter tumor
metabolism
Genomics Metabolism

10. Metabolic reprogramming is a hallmark of cancer
•8 hallmarks- each represents the successful
breaching of an anticancer defense
mechanism
•Together, these hallmarks allow cancer
cells to proliferate endlessly, avoid
apoptosis and invade surrounding tissue.
• But for our purposes today, the hallmark
that we will focus on is metabolic
reprogramming.
Hanahan & Weinberg, Cell, 144, 646-674, 2011

11. Layers of metabolic reprogramming in cancer
Three layers of metabolic
reprogramming:
• gain access to conventional and
unconventional nutrient sources
• build new biomass to sustain
deregulated proliferation
• exploit the ability of select
metabolites to affect cell fate of
both tumor cells as well as
variety of normal cell types
within the tumor
microenvironment. Pavlova et al., Cell Metabolism, 23, 27-47, 2016

12. IDH, FH and SDH mutations- paradigm shift in the role of
metabolism in cancer
• For a long time, it was thought that
metabolic reprogramming is a by-
product of tumorigenesis i.e. useful
but not central to tumorigenesis.
• But the discovery of mutations in
metabolic enzymes that drive
tumorigenesis has established that
altered metabolism is crucial
• Mutations in isocitrate dehydrogenase
(IDH), fumarate hydratase (FH) and
succinate dehydrogenase (SDH) Mutations in metabolic enzymes drive cancer!

13. Leveraging metabolism for non-invasive metabolic imaging
and therapy
Genetics
Epigenetics
Biology
Metabolic
reprogramming
Metabolic imaging Metabolic therapy
Insights from tumor genetics, epigenetics and biology can be leveraged to drive the
preclinical development of novel, metabolic imaging probes and therapeutic targets

14. Leveraging metabolism for non-invasive metabolic imaging
and therapy- Impact
Patient selection Monitoring response
to therapy
Assess tumor
heterogeneity
Pinpoint metabolic
vulnerabilities
Pretreatment genomic
analysis
• Early response
• Distinguish from
treatment-related
effects
• Evaluation of
treatment
resistance
Mutational
heterogeneity
translates into
metabolic
heterogeneity
Potential actionable
targets

15. Warburg effect- the most famous metabolic hallmark
• Described way back in the 1920’s by Otto
Warburg (pictured here)
• Tumor cells take up more glucose relative
to surrounding somatic tissue and
converted it almost exclusively to lactate.
• Most cells will convert glucose to lactate
under conditions of low oxygen tension
i.e. anaerobic conditions.
• But tumor cells convert glucose to lactate
even under conditions of normal oxygen
tension and therefore the Warburg effect
is also known as aerobic glycolysis.

16. The paradox of the Warburg effect
• The Warburg effect is inherently less
efficient for ATP synthesis.
• In the presence of oxygen, somatic tissues
first metabolize glucose to pyruvate via
glycolysis and then oxidize most of that
pyruvate in the mitochondria to CO2 via
the TCA cycle.- 36 moles of ATP for
every mole of glucose.
• When pyruvate is shunted to lactate, there
is minimal ATP production (~2 moles of
ATP per mole of glucose).
• Warburg initially thought that this was
because mitochondria were defective in
tumor cells- but mitochondria remain
functional
Vander Heiden et al., Science 324, 1029-1033, 2009

17. The Warburg effect facilitates macromolecular biosynthesis
• Although ATP yield is low, if the
glycolytic flux is high enough, ATP
production can exceed oxidative
phosphorylation.
• Glucose degradation provides
intermediates for nucleotide, lipid and
amino acid biosynthesis; and, through
the oxidative pentose phosphate
pathway, NADPH.
• So the Warburg effect benefits both
bioenergetics and biosynthesis.
Cantor & Sabatini, Cancer Discov; 2(10); 881–98, 2012

18. The PI3K/Akt/mTOR pathway is a major facilitator of the
Warburg effect in gliomas
• Many tumors, including gliomas, have
mutations that leads to aberrant activation of
the PI3K/Akt/mTOR pathway.
• The PI3K/Akt/mTOR pathway activates of
the Warburg effect.
• The transcription factor HIF-1⍺ increases
expression of glucose transporter 1 (GLUT1)
which increases glucose uptake. LDHA
expression is increased leading to the glucose
being converted to lactate.
• HIF-1⍺ also increases expression of pyruvate
dehydrogenase kinase 1 (PDK1). PDK1
phosphorylates pyruvate dehydrogenase
(PDH) and inhibits its activity. So pyruvate is
not shunted to acetyl CoA and instead is
converted to lactate.
Deberardinis et al., Cell Metab, 7(1):11-20, 2008

19. Altered cancer metabolism can be exploited for non-invasive
metabolic imaging
• The Warburg effect provides the
best example of the use of metabolic
imaging in the clinical management
of patients with cancer.
• The most common form of PET
imaging takes advantage of the high
glucose demand resulting from the
Warburg effect
• 2-[18F]-fluoro-2-deoxy-d-glucose
(18F-FDG) is a glucose analogue
that cannot be metabolized further
than initial phosphorylation by
hexokinase and accumulates in cells,
providing an indication of their
glucose demand.
Kelloff et al., Clin Can Res, 11(8), 2785-2808, 2005

20. Vander Heiden et al., Science 324, 1029-1033, 2009
• The Warburg effect provides the
best example of the use of metabolic
imaging in the clinical management
of patients with cancer.
• The most common form of PET
imaging takes advantage of the high
glucose demand resulting from the
Warburg effect
• 2-[18F]-fluoro-2-deoxy-d-glucose
(18F-FDG) is a glucose analogue
that cannot be metabolized further
than initial phosphorylation by
hexokinase and accumulates in cells,
providing an indication of their
glucose demand.
Altered cancer metabolism can be exploited for non-invasive
metabolic imaging

21. The use of 18F-FDG-PET in glioma imaging is limited
• In the imaging of gliomas, however,
18F-FDG-PET has poor tumor-
to-background contrast owing to
the generally high levels of glucose
uptake in the normal brain.
• 18F-FDG-PET also has limited
specificity in distinguishing between
tumor and nonmalignant processes,
including infection and
inflammation.
Kim et al., Nat Rev Clin Oncol, 13, 725-740, 2016

22. 13C-Magnetic resonance spectroscopy (MRS) can non-
invasively probe the Warburg effect but is limited in sensitivity
• Using 13C-labeled glucose as a
tracer, MRS can be used to
monitor glucose metabolism in
patients with gliomas
• But really long acquisition times
due to the low sensitivity of 13C-
MRS limits clinical utility
• Intriguingly, in mice
orthotopically implanted with
patient-derived GBM cells,
infusion of 13C-labeled glucose
before tumor resection and ex vivo
MRS showed considerable entry
of glucose-derived carbon into the
TCA cycle, with lower generation
of 13C-lactate than expected
Long acquisition time!
Wijnen et al., Magnetic Resonance Imaging 28, 690–697, 2010

23. Hyperpolarization increases the SNR of 13C-MRS by >10,000 fold
• Hyperpolarized 13C MR
quantifies metabolic fluxes that
were previously inaccessible to
imaging
• Endogenous, physiologically
relevant probes
• 13C nuclear spins in a labeled
substrate are hyperpolarized by
irradiation with microwaves at
low temperature and high
magnetic field
• The frozen sample is then
warmed rapidly to room
temperature and injected
intravenously into
cells/animals/patients
Transfer polarization from electron spins to the 13C nucleus
The SNR is proportional to the population difference!

24. Interrogating the Warburg effect: Hyperpolarized [1-13C]-pyruvate
• Pyruvate can be converted by
LDH to lactate or by alanine
transaminase (ALT) to form
alanine.
• Alternatively, pyruvate can be
shunted through pyruvate
dehydrogenase (PDH), which the
releases 13C moiety as as
bicarbonate.
• Thus, carbon-1 of pyruvate is
perfectly positioned to probe both
aerobic and anaerobic metabolism
simultaneously.

25. Hyperpolarized [1-13C]-pyruvate can monitor tumor burden in gliomas
• One of the earliest studies with
hyperpolarized 13C-MRS in
the brain
• Significant differences in 13C
metabolic profiles between
tumor and normal brain.
• The 13C lactate and pyruvate
levels in the contrast-
enhancing lesions of the brain
in rats with tumors were much
higher than those in the brains
of rats without tumors.
Park et al., Neuro-Oncology 12(2):133–144, 2010.

26. Hyperpolarized [1-13C]-pyruvate can monitor response to PI3K
inhibitors in glioblastomas
• PI3K/mTOR inhibitors such as
everolimus and voxtalisib are in
clinical trials for glioblastoma
patients.
• However, these inhibitors tend
to induce tumor stasis rather than
shrinkage and so it is often
difficult to monitor response to
therapy.
• Since the PI3K/mTOR pathway
activates the Warburg effect, can
we use hyperpolarized [1-13C]-
pyruvate to monitor response to
therapy?
Everolimus/LY294002/Voxtalisib

27. Hyperpolarized [1-13C]-pyruvate can monitor response to PI3K
inhibitors in glioblastomas
• PI3K/mTOR inhibitors such as
everolimus and voxtalisib are in
clinical trials for glioblastoma
patients.
• However, these inhibitors tend
to induce tumor stasis rather than
shrinkage and so it is often
difficult to monitor response to
therapy.
• Since the PI3K/mTOR pathway
activates the Warburg effect, can
we use hyperpolarized [1-13C]-
pyruvate to monitor response to
therapy?
Control Everolimus
Early biomarker of
response to therapy
Chaumeil et al. Neuroimage, 59, 193–201, 2011

28. Clinical translation of hyperpolarized [1-13C]-pyruvate in
glioma patients
• First hyperpolarized [1-13C]-
study in the brain (tumor)-
UCSF- 8 patients- all gliomas
• Unlike preclinical studies, the
normal brain shows considerable
lactate production
• Anesthesia?
• Gray matter/cortical content?
• Immune system?
• Other factors?
• But…the bicarbonate/pyruvate
ratio can still distinguish tumor
and normal brain
Park et al., Magn Reson Med, 80(3):864-873, 2018

29. Clinical translation of hyperpolarized [1-13C]-pyruvate in
glioma patients
• First hyperpolarized [1-13C]-
study in the brain (tumor)-
UCSF
• Unlike preclinical studies, the
normal brain shows considerable
lactate production
• Anesthesia?
• Gray matter/cortical content?
• Immune system?
• Other factors?
• But…the bicarbonate/pyruvate
ratio can still distinguish tumor
and normal brain Park et al., Magn Reson Med, 80(3):864-873, 2018

30. Clinical translation of hyperpolarized [1-13C]-pyruvate in
glioma and brain metastasis patients
• Hyperpolarized [1-13C]-pyruvate
in a patient with a melanoma
brain metastasis- MSKCC
• Interestingly, the volume
normalized lactate signal in the
lesion is 6.7-fold higher than the
entire brain- inherent differences
in metabolism, immune
suppression?
• Insufficient SNR for bicarbonate
Miloushev et al., Cancer Res; 78(14); 3755–60, 2018

31. Clinical translation of hyperpolarized [1-13C]-pyruvate in
glioma and brain metastasis patients
• Hyperpolarized [1-13C]-
pyruvate in a patient with an
ovarian cancer metastasis-
MSKCC
• Very high lactate production
in the normal brain- poor
tumor to background contrast
Miloushev et al., Cancer Res; 78(14); 3755–60, 2018

32. Clinical translation of hyperpolarized [1-13C]-pyruvate in
glioma and brain metastasis patients
• Hyperpolarized [1-13C]-
pyruvate in 2 patient- one
with a high-grade primary
glioblastoma and one with
low-grade
oligodendroglioma-
MSKCC
• Again, very high lactate
production in the normal
brain- poor tumor to
background contrast
Primary glioblastoma Oligodendroglioma
Miloushev et al., Cancer Res; 78(14); 3755–60, 2018

33. Imaging the IDH1 mutation (IDHmut) in gliomas
Earliest genetic alteration
Drives tumorigenesis
The Cancer Genome Atlas Research Network, N Engl J Med, 372:2481-2498, 2015
• Mutations in isocitrate
dehydrogenase (IDH) drive
tumorigenesis in the majority of
low-grade gliomas and acute
myeloid leukemia
• IDH1 in gliomas
• IDH2 in AML
• Earliest known genetic alteration in
these tumors
• Paradigm shift in defining the role
of altered metabolism in cancer

34. IDHmut results in the production of a novel oncometabolite
2-hydroxyglutarate (2-HG)
• Wild-type IDH converts isocitrate
to ⍺-ketoglutarate (⍺-KG)
• The mutant IDH enzyme
(IDHmut) converts ⍺-KG to a
novel oncometabolite 2-
hydroxyglutarate (2-HG)
• 2-HG inhibits the activity of key ⍺-
KG-dependent dioxygenases
including DNA and histone
demethylases and prolyl
hydroxylases
• This induces epigenetic and
signaling changes that ultimately
kickstart tumorigenesis

35. Hyperpolarized [1-13C]-⍺-ketoglutarate can monitor 2-HG
production in IDHmut gliomas
Chaumeil et al. Nat Commun, 4: 2429, 2013.

36. Hyperpolarized [1-13C]-⍺-ketoglutarate can monitor 2-HG
production in IDHmut gliomas
Chaumeil et al. Nat Commun, 4: 2429, 2013.

37. IDH1 mutation induces 1H-MRS-detectable metabolic
reprogramming
NHA$IDH$wt$
NHA$IDH$mut$
2HG$
Lactate$Glutamate$
Phosphocholine$
Crea;ne$
2HG$
NHA$IDH$wt$
NHA$IDH$mut$
2HG$
Lactate$Glutamate$
Phosphocholine$
Crea;ne$
2HG$
Izquierdo-Garcia et al., PLOS One, 10:e0118781, 2015
−100 −50 0 50 100
−30−20−10010203040
−40
−20
0
20
40
60
PC1(79.7%)
PC2(11.7%)
PC3(5.4%)
●
●
●
●
● ●
●
U87
−60 −40 −20 0 20 40 60 80 100
−40−2002040
−60
−40
−20
0
20
40
60
PC1(36.69%)
PC2(32.84%)
PC3(30.21%)
●
●
● ●
●●
NHA
• Compare wild-type IDH
(IDHwt) cells with IDHmut
cells to identify a metabolic
signature of the IDH1 mutation
• PCA to identify IDHmut-
induced metabolic alterations in
an unbiased manner
• Beyond production of 2-HG,
IDHmut induces a reduction in
steady-state levels of glutamate,
lactate and phosphocholine
0
1
2
3
4
5
6
7
8
9
Glutamate Phosphocholine
fmol/cell
NHAIDHwt
NHAIDHmut
*
* *
*
Glutamate Lactate Phospho
choline
2-HG

38. Glucose-derived glutamate is reduced in IDHmut glioma cells
• Can we exploit IDHmut-
induced reduction in
glutamate for metabolic
imaging and therapy?
• Glutamate can be derived
from glucose via glycolysis
and the TCA cycle
• Alternatively, glutamine can
be converted to glutamate via
glutaminolysis
• Label cells with [1-13C]-
glucose and [3-13C]-
glutamine to tease apart the
contributions
0
1
2
3
4
5
6
7
8
9
Glutamate Phosphocholine
fmol/cell
NHAIDHwt
NHAIDHmut
*
*
*
*
Glutamate Lactate Phospho
choline
2-HG
Acetyl CoA
TCA cycle
Citrate
α-KG
Succinate
Fumarate
Oxaloacetate
Citrate
Isocitrate
α-KG 2-HG
Glutamate
[3-13C]-Glutamine
IDHmut
Pyruvate
[1-13C]-Glucose
PDH
Izquierdo-Garcia, Viswanath et al., Cancer Res, 75(15); 1–11, 2015

39. Pyruvate dehydrogenase (PDH) activity is reduced in
IDHmut cells
• Pyruvate
dehydrogenase (PDH)
is a rate-limiting
metabolic checkpoint
for oxidation of
glucose via the TCA
cycle
• Significant reduction
in PDH activity in
IDHmut cells
compared with
IDHwt
0
2E-09
4E-09
6E-09
8E-09
1E-08
1.2E-08
NHAIDHwt NHAIDHmut
OD/hr/cell
***
Acetyl CoA
TCA cycle
Citrate
α-KG
Succinate
Fumarate
Oxaloacetate
Citrate
Isocitrate
α-KG 2-HG
Glutamate
Glutamine
IDHmut
Pyruvate
Glucose
PDH
Izquierdo-Garcia, Viswanath et al., Cancer Res, 75(15); 1–11, 2015

40. Mechanism: HIF-1α stabilization up-regulates PDK3
expression resulting in reduced PDH activity
0.00
0.05
0.10
0.15
0.20
0.25
Ser 293 Ser300
OD/cell
Inhibitory PDH phosphorylation
NHAIDHwt NHAIDHmut
PDH phosphorylation
NHAIDHmutNHAIDHwt
PDK3
β-tubulin
NHAIDHmutNHAIDHwt
HIF-1α
Actin
PDK3 HIF-1α
Acetyl CoA
TCA cycle
Citrate
α-KG
Succinate
Fumarate
Oxaloacetate
Citrate
Isocitrate
α-KG 2-HG
Glutamate
IDHmut
Pyruvate
PDH PDK3
Lactate DCA
HIF-1⍺
• 2-HG stabilizes HIF-
1⍺ which is normally
degraded as soon as it
is made by ⍺-KG-
dependent prolyl
hydroxylases
• HIF-1⍺ increases
PDK3 expression
• PDK3 phosphorylates
and inhibits PDH
activity
• Treating wild-type
cells with 2-HG has
the same effect
Izquierdo-Garcia, Viswanath et al., Cancer Res, 75(15); 1–11, 2015

41. Hyperpolarized [2-13C]-pyruvate can non-invasively monitor
PDH activity
Acetyl CoA
TCA cycle
Citrate
α-KG
Succinate
Fumarate
Oxaloacetate
Citrate
Isocitrate
α-KG 2-HG
[5-13C]-glutamate
IDHmut
[2-13C]-pyruvate
PDH
[2-13C]-lactate
• Flux through glycolysis
produces [2-13C]-
lactate while flux
through the TCA cycle
produces [5-13C]-
glutamate- so it can
provide a measure of
glycolytic as well as
oxidative glucose
metabolism
• Consistent with
reduced PDH activity,
hyperpolarized [5-
13C]-glutamate
production was lower
in IDHmut cells
[1-13
C]-pyruvate[1-13
C]-pyruvate
hydrate
[5-13C]-glutamate
NHAIDHwt
NHAIDHmut
ppm 0
0.5
1
1.5
2
2.5
3
3.5
NHAIDHwt NHAIDHmut
[5-13C]-glutamate
(AU/cell)
NHAIDHwt
NHAIDHmut
*
Izquierdo-Garcia, Viswanath et al., Cancer Res, 75(15); 1–11, 2015

42. Reversing PDH down-regulation using dichloroacetate
inhibits IDHmut glioma cells
0
5E-09
1E-08
1.5E-08
2E-08
2.5E-08
NHAIDHwt NHAIDHmut
PDHactivity
(OD/hr/cell)
PDH activity Control
DCA
0
20
40
60
80
100
NHAIDHwt NHAIDHmut
No.ofcolonies
Clonogenicity
Control
DCA
Acetyl CoA
TCA cycle
Citrate
α-KG
Succinate
Fumarate
Oxaloacetate
Citrate
Isocitrate
α-KG 2-HG
Glutamate
IDHmut
Pyruvate
PDH PDK3
Lactate
DCA
Dichloroacetate (DCA) is a pyruvate mimetic
that inhibits PDK3 and activates PDH
Izquierdo-Garcia, Viswanath et al., Cancer Res, 75(15); 1–11, 2015

43. Hyperpolarized [2-13C]-pyruvate can non-invasively monitor
response to dichloroacetate (DCA)
NHAIDHwt
NHAIDHmut
NHAIDHwt+DCA
NHAIDHmut+DCA
5-13
C-glutamate 1-13
C-pyruvate
Acetyl CoA
TCA cycle
Citrate
α-KG
Succinate
Fumarate
Oxaloacetate
Citrate
Isocitrate
α-KG 2-HG
[5-13C]-glutamate
IDHmut
[2-13C]-pyruvate
PDH PDK3
DCA
0
0.8
1.6
2.4
3.2
NHAIDHwt NHAIDHmut
[5-13
C]-glutamate(AU/cell)
Control DCA
*
Dichloroacetate (DCA) is a pyruvate mimetic
that activates PDH
Izquierdo-Garcia, Viswanath et al., Cancer Res, 75(15); 1–11, 2015

44. Clinical translation of hyperpolarized [2-13C]-pyruvate in
IDHmut glioma patients
GlutamateGlutamate
Chung et al WMIC 2018; Chung et al ENC 2019Data from Yan Li & Dan Vigneron
Hyperpolarized [2-13C]-pyruvate in patient with grade 2
IDHmut astrocytoma
Initial data indicates reduced conversion to glutamate in the
tumor

45. Altered glutamine metabolism is a hallmark of cancer
• Glutamine is the most-
abundant amino acid in the
plasma, and many cancers,
including brain tumors, display
increased cellular glutamine
uptake and metabolism.
• Glutamine is metabolized to
form glutamate, which can be
metabolized to form α-KG
• α-KG can enter the TCA cycle,
and thus serves as a crucial
contributor to anaplerosis and
energy production
• In brain tumors, MYC, p53,
and the PI3K/AKT/mTOR
pathways are involved in the
regulation of glutamine
metabolism.

46. Interrogating glutamine metabolism- hyperpolarized [5-13C]-glutamine
Gallagher et al., Magn Reson Med 60:253–257, 2008
Rapid, spontaneous degradation of glutamine to glutamate (product of interest) in the prep is an issue
[5-13C]-glutamate
HepG2 Lysate
HepG2 Cells
No cell control
Transport is a limiting factor

47. Interrogating glutamine metabolism- hyperpolarized [1-13C]-glutamine
Salamanca-Cardona, Cell Metabolism 26, 830–841, 2017

48. Interrogating redox status: hyperpolarized [1-13C]-
dehydroascorbic acid
Keshari et al., PNAS, 108 (46) 18606-18611, 2011

49. Interrogating redox status: hyperpolarized [1-13C]-
dehydroascorbic acid
Timm et al., J Biol Chem, 292(5), 1737-1748, 2017

50. Summary
• Altered cancer metabolism offers a unique window to integrate
genomic information with advanced imaging modalities
• Hyperpolarized 13C-MRS is unique among imaging modalities in the
ability to monitor metabolic fluxes
• The field has progressed rapidly and has been successfully translated to
the clinic
• Future studies based on oncogene-driven metabolic pathways might
enhance diagnosis, prognostication, treatment, and surveillance of
brain tumors, and ultimately improve patient outcomes.