Search

ARCHIVES
CONTACT US
WORLD NEWS

McGill U. researchers to develop genetic test for cancer

MONTREAL-A simple blood test could soon determine your chances of getting cancer, reports a study spearheaded by McGill University researchers.

"The key to curing cancer is early detection," says Greg Matlashewski, recently appointed chair and associate professor of microbiology and immunology at McGill. "It might be possible in the future to tell from DNA obtained from a blood sample, or even from a mouth scraping, whether you are susceptible to cancer."

Along with Eduardo Franco, professor of epidemiology and oncology, Matlashewski is studying the cell protein p53. When cells are infected by viruses, p53 in some cases will cause the cell to "commit suicide" in a process known as apoptosis. Apoptosis is done in an effort to keep other cells from becoming infected.

A virus such as human papilloma virus, however, can produce a gene product that can interfere with cell apoptotic mechanisms, resulting in the uncontrollable replication and multiplication of cells. The end result, in some instances, is cancer.

An earlier study in London, England found that some p53 DNA sequences were found more often in cancer patients.

Matlashewski and Franco will be using data collected from cervical cancer patients in Brazil to confirm these results.

In Canada, there are about 1,500 cervical cancer cases each year. Brazil, in comparison, has cervical cancer rates that are ten times higher. Cervical cancer is the most common form of cancer in developing countries.

"Cervical cancer is highly preventable, and many of the deaths attributed to it are unnecessary," says Matlashewski.

"Cervical cancer is very slow-growing; it typically takes five to ten years for it to develop. The Pap smear has saved millions of lives, and has been proven to be effective at saving lives."

Cervical cancer is caused by human papilloma virus, which also causes the sexually transmitted disease genital warts. In Canada, HPV is found in 10-20 percent of the population. HPV is usually not harmful, but may cause cervical lesions in one percent of those infected, potentially resulting in cancer. HPV produces the protein HPV E6, which will bind to p53, thereby inhibiting apoptosis.

Different people have different p53 DNA sequences, a phenomenon known as polymorphism. By determining which p53 sequences are more prevalent in cervical cancer, a quick, effective diagnostic test could be developed. This test could then be used in conjunction with the existing method, the Pap smear.

During the Pap smear process, cells are scraped off the surface of the cervix, then examined under a microscope for evidence of cancer. In developing countries, such as South America, Africa, and parts of Asia, access to Pap smears is limited and expensive - resulting in cervical cancer rates that can be 10 times higher than those in Canada.

With the new test, individuals who are at risk could then be monitored more closely, thus decreasing their chances of developing cancer.

Discoveries about p53 could also help in the treatment of other forms of cancer, since the majority of cancer types result from some form of p53 inhibition.

Matlashewski is also investigating new treatments against the parasite Leishmania. Leishmania is the second most common parasitic infection in developing countries, and is transmitted by sandfly insect bites. Certain types of Leishmania will cause leprosy and loss of the nose, while other types can result in breakdown of the bone marrow and eventual death.

Drs. Matlashewski and Ward (Montreal General Hospital) will be testing a new anti-Leishmania drug in Cusco, Peru. Matlashewski hopes to soon develop a Leishmania live-attenuated vaccine, for use in developing countries such as India and Peru.

The cancer study is being funded by the National Cancer Institute of Canada; the Leishmania trials are being sponsored by the World Health Organization, the Medical Research Council of Canada, and 3M Pharmaceuticals.