Altered Versions of DNA Could Serve as Biomarker for Cancer

In the past few years, new technologies and techniques have become available that allow researchers to quickly sequence large strands of DNA at a fairly affordable cost. Recently, this breakthrough has allowed researchers at Johns Hopkins University to look at DNA mutations as a possible biomarker for cancer.

As cancer cells grow and divide, they shed small fragments of mutated DNA into the circulatory system. The team at Johns Hopkins – led by Dr. Bert Vogelstein and Kenneth W. Kinzler – hypothesized that these DNA mutations could be sequenced and identified as a possible early indicator of cancer.

The process proved time-consuming, as a broad number of DNA mutations are unique in cancer cells. As such, knowing which specific mutation would serve as the best biomarker for cancer served as a major hurdle to the team.

Despite this, the researchers at Johns Hopkins have announced the formation of a lab technique that successfully identifies DNA rearrangements caused by cancer mutation. The process works by quickly sequencing DNA fragments in the blood stream.

Though very promising, a major drawback to the process is cost. Due to the need to sequence a patient’s entire genome, the estimated price tag of testing a single patient is $5,000.

According to the team’s research, which was published in the March issue of Nature, mitochondrial DNA rearrangements may serve as more cost-effective biomarkers for cancer. The reason for this is twofold. For one, mitochondrial DNA is incredibly small compared to a cell’s main strand of DNA, with just 16,000 genome units (a cell’s nucleus has three billion genome units). For two, mitochondrial DNA mutations occur in approximately 80 percent of all cancers, making the new technique a near universal option for future cancer diagnosis.

Even with these potential cost savings, fees associated with DNA sequencing will need to drop further in order to be feasible for widespread use. Still, given the strong sensitivity of the procedure, many are hopeful for the future of DNA as a cancer biomarker. According to Dr. Vogelstein, “There is no question from a research point of view that this approach has the potential to track patients and tumors better than with the conventional approach.”