What is Cancer Genomics?
All cancers arise from changes that occur in the DNA of cells. DNA is the chemical set of instructions inside each cell that tells the cell what to do. The complete set of DNA within a species is called the genome. When the DNA instructions have mistakes in them, cells may not function normally and may grow out of control, causing cancer. The study of genes associated with cancer is referred to as cancer genomics. Cancer-causing changes in DNA, called mutations, can be inherited but most are acquired throughout life. While cancer was once thought of as a single disease that affected many different parts of the body, researchers now know that there are differences in the DNA makeup of cancer cells of each patient and that changes in the cancer’s DNA can cause each cancer to have a unique behaviour. That’s why two patients who have cancer in the same part of the body may respond differently to the same treatment. Testing for mutations in cancer cells is known as molecular profiling.
Why is Molecular Profiling Important?
Genomic changes in cancer can potentially provide information on benefit or resistance to certain targeted cancer treatments. We can already see the success of targeted cancer treatments in various cancers, such as use of imatinib in chronic myelogenous leukemia (CML); trastuzumab in human epidermal growth factor receptor-2 (HER2) amplified breast; and epidermal growth factor receptor (EGFR) inhibitors in lung cancers. In addition to these approved settings and commercially available agents, there are early and promising results testing PARP inhibitors in patients with germline BRCA1/2 mutations, and ALK inhibitors in non-small cell lung carcinoma patients with ALK mutations. By looking at the molecular profile of many tumour samples from many different patients, we will be able to gain a better understanding of what makes one cancer different from another, which is important because it will help explain why two patients with the same type of cancer may respond very differently to the same treatment. By connecting specific genomic changes with specific outcomes, we will be able to develop more effective and individualized ways of treating each cancer patient.
Molecular Profiling Initiative at Princess Margaret
Targeted molecular profiling is available as standard of care in the treatment of several solid malignancies in Ontario as of 2021. Cancer Care Ontario-Ontario Health is funding testing for multiple genes in various tumor types. For the most current information, please view the test requisitions available at UHN or email the Division of Clinical Laboratory Genetics
At the Princess Margaret, the Cancer Genomics Program is offering comprehensive molecular profiling free-of-charge to our patients as part of one of our many research studies.