Imagine if cancer could be monitored by simple blood tests. Rather than through invasive bone marrow biopsies, which risk infection and can be extremely painful, cancer could be monitored by periodic blood tests, which provide detailed information for the creation of more effective personalized treatments tailored to an individual’s needs. This dream may now be a reality, as reported in a study published in Clinical Cancer Research, all made possible by advances in genome sequencing.
Image Source: Jonathan Knowles
Cancer, broadly speaking, is the unchecked proliferation of cells that have the ability to spread throughout the body, creating tumors and causing severe damage to body tissues and organs. Last year, researchers discovered that when tumor cells die, they release bits of DNA molecules, called cell-free circulating tumor DNA (cfDNA), into the blood. Follow up studies reported that the cfDNA could be studied by sequencing blood plasma samples from breast cancer patients.
The uncontrolled growth of tumor cells has been shown to be caused, in part, by mutations in DNA that arise during our lifetimes. Because these mutations are specific to tumor cells, knowing which mutations are associated with certain types of cancer theoretically allows for the detection and monitoring of cancer. Because the amount of cfDNA in blood appears to correlate with the stage of cancer and because advances in genome sequencing allow for relatively cheap and easy sequencing of cfDNA, these types of tests may soon become routine in clinical use.
This new study analyzed over 150 blood plasma samples from 39 patients with various cancer types. After identifying the cfDNA mutations specific to each patient, targeted drug treatments were administered and tracked over time. The study successfully showed that cfDNA sequencing can be used effectively to monitor the progress of drug therapy over time. Mutations were identified in 69% of the patients, and the growth or shrinking of tumors identified with CT scans matched the presence or absence of the specific cfDNA mutations being targeted by the therapy.
In summary, this study shows that cfDNA sequencing in cancer patients can identify markers to track disease progression and monitor the effectiveness of drug therapy over time. By using this non-invasive diagnostic tool, patients will receive more personalized drug therapies, and adjustments can be made throughout treatment so that doctors know when resistance to a given treatment has developed and when more effective treatments should be pursued.
Feature Image Source: blood samples by NTNU medisin og helse
