Last Updated: January 19, 2006



NEW YORK (Reuters Health) - A new method of isolating colonocytes
from naturally evacuated feces may form the basis for early detection
of colorectal cancer, according to Japanese researchers.


Investigator Dr. Yasuhiro Matsumura told Reuters Health that in
envisioning the technique "we predicted that normal mucous cells
would die and be exfoliated during turnover and that the cancer cells
would likely survive for a long time in feces."

In the December issue of Gastroenterology, Dr. Matsumura of the
National Cancer Center Hospital East, Kashiwa City and colleagues
note that they tested the feasibility of this approach by analyzing
feces from 116 patients with colorectal cancer and from 83 healthy
volunteers.

The new method involved a funnel-shaped filtration system that was
capable of filtrating the entire stool suspension without filter
clogging, the authors write. They then used magnetic beads coated
with mouse antibodies specific for a membrane antigen epressed on
most normal and neoplastic human epithelial tissues to separate cell
populations.

The researchers used both cytological and DNA techniques to examine
retrieved cells. Cytology showed atypical cells in 28% of the cancer
patients and none of the volunteers.

Genetic alterations were seen in 82 of the cancer patients, giving a
sensitivity of 71%. However, alterations were also seen in 10 of the
volunteers, yielding a specificity of 88%.

When the analysis was limited to cases in which genetic alterations
were present in cancer tissue, the detection rate for such
alterations using these methods was 86%.

Given these encouraging findings, Dr. Matsumura concluded that "we
are now planning a prospective randomized study to compare our new
method with the hemoccult test to determine the actual specificity
and sensitivity in a real screening population and to verify its
clinical usefulness and medical economics."





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