As we’ve previously discussed, the technology used to sequence a human genome has drastically improved over the past few years, making the process less expensive and more efficient. These rapid advances in the decade since the completion of the human genome project have made this technology more user-friendly and a more viable option for helping to further certain fields of medical research. One area where this is evident is in the research of cancer diagnosis and treatment.
Whole genome sequencing in patients with cancer, often works like a subtraction equation. Scientists can take two DNA samples from the same individual: one from a cancerous tumor and one from normal, healthy tissue. They then sequence both samples and “subtract,” them, or find the differences between them to discover which part or parts of the DNA are linked to the growth of the cancer. The cancer DNA can also be compared to the DNA of healthy individuals as well as other individuals with cancer so that researchers can try to determine patterns- if for example the cancerous DNA samples in several different patients have similarities.
Beginning in 2008, researchers at The Genome Institute at Washington University in St. Louis, began collecting and sequencing samples from patients with acute, myeloid leukemia (AML), a serious form of blood cancer. With the help of faster and less expensive whole genome sequencing technologies, researchers at The Genome Institute sequenced the complete genomes of cancerous and healthy cells from 150 individuals. Researchers were able to follow these patients through their treatment process and record which patients received which treatments and how successful the treatments were. They compiled this data with the genomes that they had sequenced to see if they could find any link between specific DNA sequences and the success or failure of certain cancer treatments.
In 2011, Washington University researchers published an exciting success story of using the whole genome sequence in the clinical setting. A woman presented with AML, and researchers were able to use whole genome sequencing to determine that she actually had a very rare subtype of the disease. This subtype was known to respond best to a specific type of treatment, and the woman was able to avoid a more aggressive form of medication. Without the help of whole genome sequencing, the subtype could not have been determined as easily or definitively. Successes like this one, though still relatively exceptional, show not only the great potential of whole genome sequencing as tool for diagnosing patients with cancer and providing them with the right treatment, but also how far we’ve come already in using this technology to provide better care for some of these individuals.
More Resources:
This article from the National Cancer Institute provides an overview of the history of whole genome sequencing in cancer research.
http://www.cancer.gov/ncicancerbulletin/071211/page5
This article from Oncology News discusses different ways that whole genome sequencing is being used for cancer research in different labs across the country.
http://www.genesinlife.org/sites/default/files/GenomeDoctor_0.pdf
