Despite remarkable progress in treating and curing some forms of the disease, cancers are still the leading cause of death in Canada. These statistics exemplify the urgent need for improved cancer prevention, screening, diagnostic and treatment strategies. Cancer researchers strive to understand why and how cancers form, spread and become resistant to treatment, to identify novel targets for the development of cancer therapeutics, to improve cancer diagnostics and screening strategies and to provide personalized cancer treatment planning.
Since the early 1990s, cancer researchers have turned their attention to tackling cancer at its source—changes to the DNA that makes up our genome. Through this research, scientists are learning experimentally how to "turn off" the genes that drive cancer growth, and "turn on" our body's best defenses against cancer, resulting in the progressive development of more targeted and personalized treatment strategies to make cancer a more manageable disease. This research is also revealing that there are hundreds of human genes that have the potential to cause malignancy. In some cases they are inherited and in others they remain dormant until "turned on" by an environmental trigger such as smoking, diet or an infectious disease.
What causes cancer?
Cancer starts when a healthy cell undergoes one or more genetic or epigenetic changes within specific regions of the genome that are involved in the regulation of cell growth and metabolism. Unless checked by the body's own defenses, that one cell can grow over weeks, months or even years, developing into a tumour.
If malignant, that tumour sheds "daughter" cells containing the same or more damaged genes, which can travel through the body's lymph system. These cells in turn "seed" and grow into new tumours elsewhere in the body, which is a process called metastasis. Understanding the exact genetic changes at each of these stages is the focus of genome sequencing in cancer research.
What is cancer genomics?
Analyzing the genetic basis of each individual tumour allows scientists to understand key genetic changes that drive cancer development, progression and resistance to treatment.
Every tumour is as unique as the patient from which it came. Everyone carries a unique set of genes inherited from their parents—the “normal” or inherited genome. Genetic changes to the inherited genome can influence cancer development, progression and response to treatment. Cancer genomics aims to decode each patient’s normal and cancer genomes, enabling clinicians to determine the best course of treatment tailored for each individual.
The standard therapies of surgery, radiation and chemotherapy have proven extremely successful in a variety of cancers, such as Hodgkin's disease, some childhood leukemias, early-stage leukemias and early-stage colorectal cancer. Even when these treatments cannot cure cancer, they extend and improve the quality of life for many patients. However, eliminating the cancer cell before it spreads through the body, before it grows into a tumour, or even earlier, is the ultimate goal of cancer genome research.
Genetic research in cancer includes:
Pinpointing which anti-cancer drugs will work best against specific forms of cancer in individual patients;
Finding genetic "on/off" switches in the cell's cancer processes;
Devising genetic screens to identify individuals at high risk of cancer;
Creating vaccines or viral messengers to arm the immune system against cancerous cells at an early stage;
Developing drugs and highly specialized radiation techniques targeted to early stages of cancer growth, to stop it in its tracks and prevent disease growth;
Predicting disease progression (ie., aggressiveness of the cancer) from initial biopsy samples.