Researchers from the Johns Hopkins Kimmel Cancer Center have created a blood test that can predict the risk of breast cancer recurrence and monitor the disease's response to treatment, according to recently published findings in the journal Cancer Research.
Currently, there are no good blood tests to see if there is a recurrence of breast cancer in patients without symptoms, said Saraswati Sukumar, co-director of Johns Hopkins' Breast Cancer. Standard blood tests are typically initiated only if a patient reports symptoms, such as pain or shortness of breath. In asymptomatic patients, testing can produce false positives that lead to unnecessary tests and biopsies.
Blood test detects breast cancer-specific genes
The researchers set out to create a non-invasive blood test that could be administered routinely to alert the physician and patient as soon as possible that a cancer might return. They created a test called the cMethDNA assay, which can monitors 10 breast cancer-related genes in patients' blood.
Specifically, the test determines whether hypermethylation—a process that silences genes that prevent cancers from spreading—is present in any of the breast cancer genes. Evidence of hypermethylation serves as an indicator that the cancer is likely to recur.
The researchers conducted a series of experiments to test the accuracy of the cMethDNA assay. The experiments found that:
- The blood test was 95% accurate in identifying patients with recurrent metastatic breast cancer from healthy women without the disease; and
- By monitoring levels of DNA methylation in patients undergoing chemotherapy, the test was able to determine in just two weeks whether a patient was responding to treatment.
The researchers also determined that the cMethDNA assay could also be used to detect recurrent lung and colorectal cancers.
Sukumar emphasized the test's ability to signal a decrease in methylation weeks before standard imaging techniques could. "Detecting early on whether or not the treatment is working for a patient can greatly help prevent unnecessary exposure to highly toxic agents, save time and help initiate other treatments more likely to be beneficial," she added (Whiteman, Medical News Today, 4/15).