Applying Genomics to Cancer
Genomics is the study of complex sets of genes, how they are expressed in cells (what their level of activity is), and the role they play in biology. Another way to think about it is as a small network of genes and how they work together to influence the cancer’s biology and response to treatment.
The Human Genome Project identified approximately 25,000 genes of the human genome. Research continues to obtain the necessary knowledge that would allow genomic information to impact treatment planning for cancer. Actionable insight from genomic information comes from understanding how these genes interrelate and what those resulting functions are, in addition to our knowledge of their sequences or forms.
Though genomics and genetics may sound similar and are related, each focuses on different information.
Broadly speaking, genetics is the study of how inherited traits are passed from one generation to the next through the genes, and how new traits appear by way of genetic mutations or changes. These traits may be characteristics such as eye or hair colour.
A predisposition to certain types of diseases can also be passed through the genes, such as the BRCA1 gene and the BRCA2 gene, which normally help control cell growth. A person who inherits an altered version of the BRCA1 and/or BRCA2 gene(s) has a higher risk of developing breast and ovarian cancer. There are breast cancer genetic tests for both the BRCA1 gene and the BRCA2 gene but these are different from the Oncotype DX® test for invasive breast cancer, which is a genomic test.
A genomic test, such as the Oncotype DX test for invasive breast cancer, looks at groups of genes and how active they are. This activity can influence how a cancer is likely to grow and respond to treatment. Unlike a breast cancer genetic test, the Oncotype DX breast cancer test does not provide information about a person’s inherited genetic make-up; instead it looks at genes in a patient’s breast tumour to understand how these genes interact and influence the tumour’s behaviour.
As the study of genomics advances, the application of genomic information is expected to enhance the diagnosis, prognosis and treatment of many different diseases, including cancer.
The key to effectively using clinical genomics to improve cancer treatment and outcomes lies in determining which sets of genes and gene interactions affect different subsets of cancers. Genomic Health is conducting studies in an effort to understand which patterns of gene expression, within a tumour are linked to a response to cancer therapy or to the likelihood that the cancer will return or metastasise. The results of these genomic studies and research can then be used to develop clinically validated tests that provide the genomic profile of an individual's tumour, helping understand whether patients are likely to benefit from and respond to cancer therapies such as tamoxifen (for breast cancer) or chemotherapy, or whether those patients are likely to experience a recurrence of their cancer.