New Blood-based Assay May Help Predict Breast Cancer Recurrence
A non-invasive blood-based assay called cMethDNA has shown high sensitivity in early detection of breast cancer recurrence. The assay also showed promise as a viable tool in predicting treatment outcome in patients.
Saraswati Sukumar, professor of oncology and pathology at the Johns Hopkins University School of Medicine in Baltimore, Md., said, “Currently, the parameters used to find out whether a patient has had a recurrence after being treated successfully is mostly self-reported complaints, followed by imaging studies. Our goal was to develop a noninvasive assay that can potentially detect recurrence in breast cancer patients before traditional methods, and administer this test during their scheduled visits.”
cMethDNA is built on a panel of 10 breast cancer-specific genes. Blood samples from patients with breast cancer are processed to isolate circulating tumor DNA. The assay detects if any of the 10 genes are hypermethylated — a process in which anti-cancer activities of certain genes are silenced. If hypermethylation in any of the genes is detected, the assay indicates that the patient may have a disease recurrence.
“Using cMethDNA, we were able to detect a drop in methylation levels as early as two weeks, and weeks before traditional imaging methods can detect a recurrence. 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,” Professor Sukumar said.
The researchers conducted a large-scale, genomewide search for genes particularly found to be methylated in the tumor tissues and blood of cancer patients. A panel of selected genes was tested in independent samples from patients who were involved in prospective clinical trials.
The 10 genes in the panel include seven novel markers (AKR1B1, COL6A2, GPX7, HIST1H3C, HOXB4, RASGRF2, and TM6SF1) and three previously described markers (ARHGEF7, TMEFF2, and RASSF1). The researchers confirmed that cMethDNA detected the presence of cancer DNA in the serum with a sensitivity and specificity higher than 90 percent.
Data from the study were published in Cancer Research, a journal of the American Association for Cancer Research.