Ovarian Cancer Detected Using Neighboring Cells,
Raises Hope for Early Detection Method
Partial wave spectroscopic (PWS) microscopy has shown
promising results in early detection of colon, pancreatic and lung
April 22, 2013 – No reliable early detection method
for ovarian cancer currently exists but there is new hope with a
discovery that has the potential as a minimally invasive early detection
method using cells collected by a swab, exactly like a Pap smear.
Pioneering biophotonics technology developed at
Northwestern University is the first screening method to detect the
early presence of ovarian cancer in humans by examining cells easily
brushed from the neighboring cervix or uterus, not the ovaries
A research team from Northwestern and NorthShore
University HealthSystem conducted an ovarian cancer clinical study at
NorthShore using partial wave spectroscopic (PWS) microscopy. They saw
diagnostic changes in cells taken from the cervix or uterus of patients
with ovarian cancer even though the cells looked normal under a
In previous Northwestern-NorthShore studies, the
PWS technique has shown promising results in the early detection of
colon, pancreatic and lung cancers using cells from neighboring organs.
If commercialized, PWS could be in clinical use for one or more cancers
in approximately five years.
The ovarian cancer study was published this month
by the International Journal of Cancer.
PWS uses light scattering to examine the
architecture of cells at the nanoscale and can detect profound changes
that are the earliest known signs of carcinogenesis. These changes can
be seen in cells far from the tumor site or even before a tumor forms.
"We were surprised to discover we could see
diagnostic changes in cells taken from the endocervix in patients who
had ovarian cancer," said Vadim Backman, who developed PWS at
Northwestern. "The advantage of nanocytology -- and why we are so
excited about it -- is we don't need to wait for a tumor to develop to
Backman is a professor of biomedical engineering at
the McCormick School of Engineering and Applied Science. He and his
longtime collaborator, Hemant K. Roy, M.D., formerly of NorthShore, have
been working together for more than a decade and conducting clinical
trials of PWS at NorthShore for four years. Backman and Roy both are
authors of the paper.
"The changes we have seen in cells have been
identical, no matter which organ we are studying," Backman said. "We
have stumbled upon a universal cell physiology that can help us detect
difficult cancers early. If the changes are so universal, they must be
Ovarian cancer, which ranks fifth in cancer
fatalities among American women, usually goes undetected until it has
spread elsewhere. The cancer is difficult to treat at this late stage
and often is fatal.
"This intriguing finding may represent a
breakthrough that would allow personalization of screening strategies
for ovarian cancer via a minimally intrusive test that could be coupled
to the Pap smear," Roy said.
At the time of the ovarian cancer study, Roy was
director of gastroenterology research at NorthShore and worked with Jean
A. Hurteau, M.D., a gynecological oncologist at NorthShore. (Hurteau is
an author of the paper.) Roy is now chief of the section of
gastroenterology at Boston University School of Medicine and Boston
The study included a total of 26 individuals. For
cells taken from the endometrium (part of the uterus), there were 26
patients (11 with ovarian cancer and 15 controls); for cells taken from
the endocervix, there were 23 patients (10 with ovarian cancer and 13
controls). The small size of the study reflects the difficulty in
recruiting ovarian cancer patients.
Cells were placed on slides and then examined using
PWS. The results showed a significant increase in the disorder of the
nanoarchitecture of epithelial cells obtained from cancer patients
compared to controls for both the endometrium and endocervix studies.
The cells for the ovarian cancer study were taken
from the cervix and uterus. For the earlier lung cancer study, cells
were brushed from the cheek. For the colon, cells came from the rectum,
and for the pancreas, cells came from the duodenum. Cells from these
neighboring organs showed changes at the nanoscale when cancer was
PWS can detect cell features as small as 20
nanometers, uncovering differences in cells that appear normal using
standard microscopy techniques. PWS measures the disorder strength of
the nanoscale organization of the cell, which is a strong marker for the
presence of cancer in the organ or in a nearby organ.
The PWS-based test makes use of the "field effect,"
a biological phenomenon in which cells located some distance from the
malignant or pre-malignant tumor undergo molecular and other changes.
In addition to Backman, Roy and Hurteau, other
authors of the paper include Dhwanil Damania, Hariharan Subramanian,
Lusik Cherkezyan, all from Northwestern, and Dhananjay Kunte, Nela
Krosnjar and Maitri Shah, all from NorthShore University HealthSystem.
Backman, Roy and Subramanian are co-founders and/or
shareholders in Nanocytomics LLC.
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