Cancer is a generic term describing a large group of diseases which are characterized by the uncontrolled growth and spread of abnormal cells. If the spread of these cancerous cells is not controlled or stopped, death results. Since cancer strikes not only people, the animal and plant kingdoms as well, it affects virtually every sphere of our society.

 

One out of every four Canadians will have cancer during his or her lifetime. In fact, of every five deaths from all causes in North America, one is from cancer. This dread disease kills more children from ages 3 to 14 than any other disease, and it strikes more frequently with advancing age. It is the second leading cause of death in Canada overall.

 

While some cancers appear to be viral in origin, most are caused by chemical carcinogens in our environment. Theories about genetic and environmental causes of cancer make use of cell culture, biochemical and other in vitro techniques, as well as computer modeling. Yet virtually every aspect of cancer research advances involved animals at some stage during its development.

 

In the 1930's, fewer than one in five people with cancer was alive five years after diagnosis. Today, the facts that almost half of those with cancer live at least five years after treatment, and that many cancers are completely curable if detected and treated promptly, are a direct result of the advances made using animal models in cancer research.

 

The methods used to diagnose cancer were also dependent on animal models in their development. The computer-assisted tomographic scan, or CAT scan (pictured at left) for example, is the most commonly used method of diagnosing cancer.

 

This technique was first tested on pigs and other animals, and the researchers responsible for this advance received the Nobel Prize in medicine in 1979 for their work.

 

The flexible endoscope, used in millions of people world-wide to diagnose early cancer of the lungs, stomach and colon, required animals at certain stages in its development. The development of monoclonal antibodies, which are used for cancer diagnosis, detection and experimental treatment, required animal research. Surgical techniques used in the removal of cancerous tissue are also highly dependent for their development on animal models.

 

Cancer Research

Cancer research as we know it today began over 35 years ago, at a time when little was known about the growth and behavior of normal cells. For this reason, many of the important questions about normal cell behavior had to be answered first by basic biomedical research, before cancer cells could be studied. An understanding of normal and tumor cell growth and interactions can only be achieved in animal models, where the interrelationships among the normal and cancerous cells can be studied intimately.

 

Current cancer research is very exciting indeed, and new developments are just around the corner.  One example of the experimental therapy currently being researched involves the use of immunotoxins, such as the normally lethal diphtheria toxin, to target cancer cells. This therapy looks promising for the treatment of T-cell leukemias, as well as malignant melanoma, a form of skin cancer. Researchers are also developing vaccines against certain types of cancers.

 

A Profile of Canadian Researchers
in the Fight Against Cancer

 

In the early 1950's, Dr. Harold Johns developed the Cobalt Unit, an effective tool for radiation therapy (which is still used around the world).   In 1968, with a grant from the National Cancer Institute of Canada, Dr. Phillip Gold and Dr. Samuel Freedman discovered the antigen name CEA during growth of cancer cells of the digestive system. This led to a revolutionary new field of research: blood testing for cancer.   In the 1970's, Dr. Anthony Miller determined the effectiveness of the Pap smear technique, to screen for cancer of the uterus. His results clearly showed that, for women aged 30 to 64, screening is significantly linked to a decline of deaths due to cancer of the uterus.   In the 1980's, Dr. Anthony Payson discovered that a certain protein module plays a vital role in transmitting cancer inducing signals within malignant cells. This led to a new understanding of the molecular "language" which controls the behaviour of cells (and the breakdown in this language which can lead to cancer).   In the 1990's, Dr. Steven Narod was part of an international team responsible for the discovery and isolation of the gene suspected of causing up to 4% of breast cancers and 10% of ovarian cancers. This may soon lead to better prevention and treatment strategies for these types of cancer.   In 1997, Dr. Norman Boyd produced the first solid evidence that women who switch to a low-fat, high carbohydrate diet can significantly reduce breast tissue density - one of the major risks for breast cancer.