The news hits you like a ton of bricks: “You have leukemia.” But there is hope for the future.
By Joël Leblanc
Only after that initial blow will patients learn that leukemia is not a single disease, but rather a group of diseases. In 2015, 6,200 Canadians will receive this diagnosis and 2,700 will not survive it.
“There are several types of leukemia,” explains Dr. Guy Sauvageau, lead investigator at the Institute for Research in Immunology and Cancer (IRIC) of Université de Montréal and hemato-oncologist at Maisonneuve-Rosemont Hospital. “What they all have in common is an abnormal proliferation of blood cells in bone marrow and blood. But initially the problem can be triggered by many different genetic anomalies.”
“The catch is that the tests currently used to establish a prognosis are inaccurate, leaving doctors with no tools to guide their decision making about treatment options.”
To understand leukemia it helps to know that it is a form of cancer. Contrary to popular belief, it is not a cancer of the blood, but of the bone marrow. In healthy people, bone marrow cells divide into various types of blood cells.
If they become lymphoid stem cells, they will develop into lymphocytes (a type of white blood cell). If they become myeloid stem cells, they will produce other cell types: red blood cells, platelets and two other kinds of white blood cells (monocytes and granulocytes). These cells then travel through the bone marrow to the bloodstream. Millions of blood cells are produced every day to replace those that naturally die off.
But when a stem cell in the bone marrow becomes cancerous, it begins to divide uncontrollably and produces a surplus of specific types of cells, which are often nonfunctional. If the problem affects the lymphoid cells, it will cause lymphoid leukemia. If it involves the myeloid cells, it will result in myeloid leukemia.
The disease is further subdivided into chronic or acute and based on other more complex criteria.
“Certain types of leukemia are relatively easier to treat than others,” Dr. Sauvageau explains. “For example, acute lymphoid leukemia, the most common form in children, has a cure rate of 80 percent. Acute myeloid leukemia, on the other hand, is a more aggressive form and leads to the death of most patients within two years of diagnosis. At the moment, there are no test to establish an acurate prognosis.”
The dream of Dr. Sauvageau and his team is to find a way to quickly identify the type of leukemia affecting a patient in order to know the prognosis and improve the person's chances of survival.
The wonderful thing about dreams is that some of them actually do come true. The Leucegene project launched in 2009 by Dr. Guy Sauvageau and Dr. Josée Hébert of Maisonneuve-Rosemont Hospital will soon provide hemato-oncologists with the tools they need to rapidly and accurately detect the type of leukemia affecting their patients.
“It’s a test on the genetic makeup of leukemia cells that will detect the genetic anomalies involved and help doctors choose the appropriate treatment right away.”
To develop this test, we are using the Quebec Leukemia Cell Bank, which is spearheaded by Dr. Josée Hébert. It is a collection of over 850 frozen leukemia cells used by researchers to gradually make a list of all genetic anomalies involved in each type of leukemia.”
There is now hope thanks to a team of seasoned scientists funded by Génome Québec and Genome Canada.