How is gene science applied to cancer?

There are 100's of human genes that have the potential to cause malignancy. In some cases they are inherited and in other cases, they are dormant until "turned on" by an environmental trigger such as smoking, a high-fat diet, or a virus.

Cancer starts as a genetic change in one cell. A healthy cell will undergo more than a dozen genetic changes (mutations in specific genes) in a precise sequence before becoming a pre-cancerous and then a cancerous cell. Unless checked by the body's own defenses, that one cell can grow to be an identifiable "cancer" tumour. Sometimes this process takes many years. A malignant tumour can then shed daughter cells, also containing the damaged genes, which usually travel through the body's lymph system. These cells in turn "seed" and grow into new tumours, a process called metastasis. Understanding the exact genetic processes at each of these changes is the focus of genome sequencing in cancer research. The analysis of tumour samples allows us to pinpoint these genomic changes leading to treatments which can specifically target tumour cells or possibly identify therapies that could halt or reverse these specific genetic changes, therefore blocking tumour growth.

The standard therapies of surgery, radiation and chemotherapy are 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.