Biology Reference
In-Depth Information
microarray,
7,50
but all of these labels refer to the
same platform.
RPMA was originally developed to quantita-
tively measure numerous proteins extracted
from a small number of cells obtained from
tissue microdissection.
35,45,78,79,100,104
e
107
How-
ever, investigators recognized that the tech-
nology was equally useful for preclinical
studies using cell lines or heterogeneous tissue
samples,
1,39,47
effectively treat each patient
s disease while
minimizing toxicity and sparing unnecessary
treatment.
RPMA is an example of an
'
technology
that has been complemented by parallel technol-
ogies and a host of supporting protocols that
speci
“
omic
”
cally address the sources of preanalytical
variability, while maximizing the sensitivity
and precision of the assay. These supporting
technologies range from laser capture microdis-
section and specialized one step
lines,
67,74,85,90,96,102,103
cell
and
serum/plasma.
2,18,71,83,86
RPMA makes it possible to evaluate the state
of entire portions of a signaling pathway or
cascade, even though the cell is lysed, by quanti-
tatively analyzing phosphorylated, glycosylated,
acetylated, cleaved, or total cellular proteins
from multiple samples printed on a series of
identical arrays.
58,104
e
106
Many identical arrays
can be measured in parallel using commercially
available antiphosphoprotein or other speci
fixation chemis-
tries to reduce preanalytical variability to
standardized nitrocellulose coated slides and
instrumentation for arraying, staining, and
image analysis.
71
For this reason, RPMA tech-
nology has moved rapidly from the laboratory
to the clinical research arena. RPMA is recog-
nized as being uniquely suited for broad-scale
pro
ling the state of
in vivo
kinase signaling
networks from human clinical tissue samples
due to the minimal total cellular volume require-
ments (a lysate from ~15,000 cells can be effec-
tively pro
c
antibodies.
94
led with over 150 proteins), high
sensitivity (femtogram
e
attogram range), and
good precision (
RPMA IN THE MOLECULAR
ONCOLOGY CLINIC
15% CV).
19,76,84,97,100
<
Personalized therapy based on an individual
patient
Protein Stability and Preanalytical
Variability
Cells within a tissue biopsy react and adapt to
the trauma of excision, ischemia, hypoxia,
acidosis, accumulation of cellular waste, absence
of electrolytes, and temperature changes.
24,93
It
would be expected that a large surge of stress,
hypoxia, and wound repair
e
related protein
signal pathway proteins and transcription
factors will be induced in the tissue immediately
following procurement.
53,54
Investigators in the
past have worried about the effects of vascular
clamping and anesthesia, prior to excision on
the
le is a dream
based on strong experimental rationale that is
now being validated in clinical research trials
for a variety of cancer subtypes. Clinicians and
laboratory scientists agree that
'
is tumor molecular pro
”
when it comes to molecular data collected from
an individual patient
“
more is better
'
stumorsample.
“
More
data
in this case means the full complement
of genomic, proteomic, and metabolic analytes.
Nevertheless, the quality of the data may be
even more important than the quantity of
data. Molecular information has to be free of
bias caused by preanalytical variables, and the
measurementplatformmustbeofsuf
”
fidelity of molecular data in tissues.
15
A much more signi
cient
sensitivity and precision. Quantity must be
matched by quality and precision to insure
that the diagnostic molecular portrait will
provide the optimal
cant and underappreciated
issue is the fact that excised tissue is alive and
reacting to
ex vivo
stress (Espina et al., 2008)
24
.
During the
ex vivo
time period, because the tissue
information required to
Search WWH ::
Custom Search