Genetic Testing & Genome Sequencing – Changing How We Treat Cancer
Genetic testing has been skyrocketing in popularity over the last few years, especially with the rapid growth of the over-the-counter consumer genetic tests from services like Ancestry and 23andme. While these tests are much more limited than the genetic profiling that we do at Personalized Hematology and Oncology of Wake Forest, they do provide a lot of interesting and useful information about an individual’s health and family history.
Difference between consumer genetic tests and tumor genome testing
The key difference between these types of genetic tests are the number of genomes sequenced. It simply isn’t feasible for consumer companies to sequence the entire genome, so often these consumer tests use genotyping to look at a specific section of the genome. While these tests can provide a lot of useful information, often they are looking at only .025% of the human genome – a very tiny fraction.
At Personalized Hematology and Oncology of Wake Forest, we create a gene expression profile from a tumor biopsy that examines more than 20,000 genes in the tumor, allowing a much more detailed look at the complete genome. A gene expression profile test identifies all of the genes in a cell that makes messenger RNA, providing far more information than an over the counter test can give you.
How is genetic testing changing the cancer treatment industry?
Cancer treatments are becoming more effective; however, there are still a number of cases where tumors simply fail to respond to current treatment methods. When this happens, it is often beneficial for a patient to undergo genetic testing of their tumor, this will allow your doctor to see specific mutations in the tumor’s genome and help identify possible treatments and clinical trials that will help specifically target a patient’s cancer.
One of the biggest issues affecting the adoption of these techniques lies with insurance companies. Typically, insurance companies will cover the DNA sequencing of a tumor if there is sufficient evidence to support that a test is necessary, but often times these tests are considered experimental and not covered by insurance.
The greatest effect that genetic testing has on cancer treatment is helping solve the challenge for modern oncologists to select the most effective anti-cancer treatment for a patient. There are over 400 FDA approved drugs on the market and in clinical trials for the most common types of cancer and navigating which will work best for a certain patient can be difficult. Genetic testing can not only narrow a patient’s options but will allow oncologists to select the best treatment for a patient based on a drug’s mechanism of action that most optimally matches the molecular mechanism driving the growth of that tumor, provided better end-results in treatment.
Further reading: Developing Pathway Collection for Personalized Anti-cancer Therapy by Luminita Castillos and Anton Yuryev