One in eight women will be diagnosed with breast cancer during her
lifetime. The earlier cancer is detected, the better the chance of
successful treatment and long-term survival. However, early cancer
diagnosis is still challenging as testing by mammography remains
cumbersome, costly, and in many cases, cancer can only be detected at an
advanced stage. A team based in the Dept. of Biomedical Engineering at
McGill University's Faculty of Medicine has developed a new
microfluidics-based microarray that could one day radically change how
and when cancer is diagnosed. Their findings are published in the April
issue of the journal Molecular & Cellular Proteomics.
For years, scientists have worked to develop blood tests for cancer
based on the presence of the Carcinoembryonic Antigen (CEA), a protein
biomarker for cancer identified over 40 years ago by McGill's Dr. Phil
Gold. This biomarker, however, is also found in healthy people and its
concentration varies from person to person depending on genetic
background and lifestyle. As such, it has not been possible to establish
a precise cut-off between healthy individuals and those with cancer.
"Attempts have been made to overcome this problem of person-to-person
variability by seeking to establish a molecular 'portrait' of a person
by measuring both the concentration of multiple proteins in the blood
and identifying the signature molecules that, taken together, constitute
a characteristic 'fingerprint' of cancer," explains Dr. David Juncker,
the team's principal investigator. "However, no reliable set of
biomarkers has been found, and no such test is available today. Our goal
is to find a way around this."
Dr. Mateu Pla-Roca, the study's first author, along with members of
Juncker's team, began by analyzing the most commonly used existing
technologies that measure multiple proteins in the blood and developing a
model describing their vulnerabilities and limitations. Specifically,
they discovered why the number of protein targets that can be measured
simultaneously has been limited and why the accuracy and reproducibility
of these tests have been so challenging to improve. Armed with a better
understanding of these limitations, the team then developed a novel
microfluidics-based microarray technology that circumvents these
restrictions. Using this new approach, it then became possible to
measure as many protein biomarkers as desired while minimizing the
possibility of obtaining false results.
Juncker's biomedical engineering group, together with oncology and
bioinformatics teams from McGill's Goodman Cancer Research Centre, then
measured the profile of 32 proteins in the blood of 11 healthy controls
and 17 individuals who had a particular subtype of breast cancer
(estrogen receptor-positive). The researchers found that a subset of six
of these 32 proteins could be used to establish a fingerprint for this
cancer and classify each of the patients and healthy controls as having
or not having breast cancer.
"While this study needs to be repeated with additional markers and a
greater diversity of patients and cancer subsets before such a test can
be applied to clinical diagnosis, these results nonetheless underscore
the exciting potential of this new technology," said Juncker.
Looking ahead, Juncker and his collaborators have set as their goal
the development of a simple test that can be carried out in a
physician's office using a droplet of blood, thereby reducing dependence
on mammography and minimizing attendant exposure to X-rays, discomfort
and cost. His lab is currently developing a hand-held version of the
test and is working on improving its sensitivity so as to be able to
accurately detect breast cancer and ultimately, many other diseases, at
the earliest possible stage.
This study was funded by the Canadian Institutes for Health Research
(CIHR), Genome Canada; Génome Québec; The Canada Foundation for
Innovation (CFI), The Natural Science and Engineering Research Council
(NSERC); and the Banque de tissue et de données of the Réseau de la
Recherches sur le cancer (RRCancer) of the Fonds de recherche en santé
du Québec (FRSQ).
Journal Reference:
- M. Pla-Roca, R. F. Leulmi, S. Tourekhanova, S. Bergeron, V. Laforte, E. Moreau, S. J. C. Gosline, N. Bertos, M. Hallett, M. Park, D. Juncker. Antibody Colocalization Microarray: A Scalable Technology for Multiplex Protein Analysis in Complex Samples. Molecular & Cellular Proteomics, 2011; 11 (4): M111.011460 DOI: 10.1074/mcp.M111.011460
Courtesy: ScienceDaily
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