Medicine is changing. The “one-size-fits-all” approach to medicine doesn’t work anymore. At Providence Cancer Center we will develop a unique treatment plan tailored to your genetic makeup and train your immune system to fight your cancer.
Your genome is your body’s instruction manual for “you.” It is the unique collection of DNA in your cells that encodes everything from hair and eye color to how you taste different foods. It also plays a role in how and when you get sick, how you recover and how your body responds to different medicines.
Cancer is often called a disease of the genome. Cancer occurs when certain changes to the genome, called “mutations,” change how our cells grow and divide. Mutations can occur in different ways, some environmental and some inherited from our parents.
The good news is that many of the mutations that cause cancer are also weaknesses that we can target to kill cancer cells. By sequencing the genome of your tumor, we seek to map out all of these mutations to come up with a personalized treatment plan.
There are two main reasons why your doctor may want to examine all or part of your genome:
The Providence Molecular Genomics Laboratory is a state-of-the-art genome center employing the latest in sequencing technology. The current approach, widely used today, is called “massively-parallel sequencing”, and allows for the simultaneous sequencing of millions of DNA fragments, allowing us to identify a large number of mutations across the genome in a matter of hours or days. This is in contrast to what was done in the past, where only tiny regions of the genome could be examined one at a time, by laborious means.
With advances in modern technology, we can perform DNA sequencing with small amounts of biological material. For tumor sequencing, a small biopsy of the tumor or a subsection taken during surgery is typically adequate. Leftover biopsy specimens that were obtained for other medical testing can usually be adapted for DNA sequencing. Moreover, because DNA is generally quite stable, historical specimens that have been stored for many years have been shown to be suitable for sequencing.
If an inherited cancer syndrome is suspected, sequencing can be performed on a small blood sample, saliva sample, or inner cheek swab.
When a sample is submitted to the lab, the first step is DNA purification. Trained lab personnel use chemical processes to extract DNA from the sample, and to remove proteins and other contaminants that may affect sequencing. A series of biochemical reactions is then performed on the purified DNA sample to make it suitable for sequencing. Lastly, the sample is loaded on the sequencer.
Following sequencing, a specific type of doctor called a molecular pathologist will investigate your genomic data to identify what mutations, if any, are present, and how these mutations relate to your cancer and any possible treatment options. Your doctors will look at similar cases across the health care system to see how other patients with similar mutations have responded to specific types of therapy. Using this information, often together with other medical tests, your doctors will develop a treatment plan that is specifically tailored to fighting your specific cancer.
While personalized medicine is a relatively new field, every year more and more mutation-targeted therapies are being approved for use in the clinic. Depending on what is found in your genomic profile, an FDA-approved targeted therapy may be recommended for treating your tumor. Certain mutations in your tumor also may qualify you for research studies of new therapies currently in the testing phase. However, in many cases the mutations identified in your tumor may not respond to treatment, and your doctors may explore alternate strategies such as immunotherapies.
Targeted immunotherapy is at the forefront of immunotherapy research. This field combines genomics with immunology, which trains the immune system to recognize mutations specific to your tumor. While there are multiple strategies for doing this, the typical workflow is the same:
- Using genomic sequencing of your tumor, we identify the novel mutations that are present.
- We take a sample of your immune cells and train or modify those cells to recognize one or more mutations present in the tumor.
- We put your modified tumor-recognizing immune cells back into your body.
While this field is still emerging, there have been tremendous successes treating patients with targeted immunotherapy in cases where all other therapies have failed.
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If you have a family history of cancer, but have not been diagnosed with cancer yourself, talk to your doctor about your family history and whether genetic testing is right for you. You may be referred to a specialist, called a genetic counselor.
If you have been diagnosed with cancer, talk to your doctor about genomic testing options. The usefulness of genomic testing varies depending on cancer types and availability of therapies.
Whether your insurance will cover genetic or genomic testing often depends on the type of cancer diagnosis and treatment options available. Contact your insurance company to determine whether your testing is covered.
- Your doctor will obtain a sample of your tumor.
- DNA will be obtained from your biological sample.
- Your DNA sequence will be read by a sequencing machine.
- Your doctors will analyze the sequencing data for potential “driver” mutations.
- A comprehensive report will be issued to your doctors detailing the sequencing results.
- Your doctors will build an action plan based on these and other results.