Fla. — Scientists have pioneered a new approach to
detecting cancer cells, one that could eventually
allow doctors to discover many malignancies earlier
than currently possible.
The scientists at the University
of Florida have successfully tested the technique
to find leukemia cells and believe that it opens
the door to the first systematic approach to diagnosing
cancer at the molecular level. Not only that, but
what they describe as a potentially new cancer
probe may one day offer a better method of targeting
individual cancer cells with drug therapies, reducing
side effects from chemotherapy treatments that
today affect both healthy and sickly cells.
“We can use this probe to recognize cancer cells,” potentially
discovering cancer earlier than often occurs today,
said Dihua Shangguan, a UF postdoctoral associate
in chemistry and the first author on a paper about
the approach that appears today in the online edition
of the Proceedings
of the National Academy of Sciences .
Contrary to popular perception, pathologists today
diagnose the vast majority of cancers based on the
shape or other characteristics of tumor tissue or
diseased cells, said Ying Li, one of nine UF faculty
members and graduate student co-authors of the paper.
That's a problem because it often means that cancers
may already be advanced when detected.
“Normally, definitive diagnosis of cancer requires
a visual examination of the tumor, which is an invasive
and time-consuming process,” explained Weihong Tan,
a UF professor of chemistry and lead author of the
paper. “Most importantly, this process is not suitable
for early detection, when the cancer is at its most
Clinicians can sometimes use antibodies, proteins that recognize and fight
bodily intruders, to identify different types of cancer. That's the case, for
example, with the prostate-specific antigen test for prostate cancer. Antibodies
are preferable to diagnosis by appearance because they are consistent and accurate,
but they are only available for a selected few cancers, Li said.
Tan, a member of the UF
Shands Cancer Center and the UF
Genetics Institute , said that scientists know
that cancer tissue has a unique molecular fingerprint
that can distinguish it from healthy tissue. But
attempts to target cells via these fingerprints
have largely proved futile because there are few
molecular tools to recognize the fingerprints.
The UF team sought to create these tools in the
form of aptamers, or short strands of chemically
synthesized DNA. These aptamers exploit the differences
on the surface of cells to discern cancerous ones.
Key to the approach is it does not require prior
knowledge of cancer indicators, Tan said.
“Using the cell-based aptamer selection strategy,
we can generate aptamers which can specifically recognize
any kind of cells without prior knowledge of molecular
changes associated with the disease,” he said.
In experiments, the researchers showed they could
successfully design sets of aptamers that would recognize
leukemia cells that had been mixed in with normal
bone marrow cells. The aptamers also successfully
distinguished leukemia T-cells from lymphoma B-cells.
Both results indicate that the aptamer method could
be used to identify many different types of cancer,
Clinicians using such molecular probes should be
able to “find cancer in a much earlier stage when
the tumors are much smaller,” enabling doctors to
begin treatment earlier, Li said.
Zare , a professor and chairman of the Stanford
University department of chemistry, said he
is “hugely impressed” by the findings reported
in the PNAS paper.
“It represents a most clever, new approach to using
the differences at the molecular level between any
two types of cells for the identification of molecular
signatures on the surface of targeted cells,” he
said. “I can easily imagine that it will have a most
significant impact on developing therapies for disease
The researchers are now testing the approach on
lung cancer cells, liver cancer cells and cells infected
by viruses, said UF chemistry post doctoral associate
Zhiwen Tang. The paper's other authors are Zehui
Charles Cao, William Chen, Prabodhika Mallikaratchy,
Kwame Sefah and Chaoyong James Yang. The work has
been funded with grants from the National
Institutes of Health , the National
Science Foundation and with a seed grant from
the office of the UF
Vice President for Research .
Writer Aaron Hoover, firstname.lastname@example.org ,
352-392-0186 Source Weihong Tan, email@example.com ,
352-846-2410 Source Ying Li, firstname.lastname@example.org ,
352-392-5621, Ext. 72052