When a patient with metastatic breast cancer undergoes a new treatment to keep the disease in check, it’s important to know how well it’s working and if the treatment should continue. A new tool in development by Johns Hopkins could make this process easier.
Researchers at Johns Hopkins Kimmel Cancer Center have created an automated liquid biopsy that they say can detect the presence of cancer DNA within five hours in the blood of metastatic breast cancer patients. The test is currently a prototype for research use only, but there is hope that oncologists could use it to determine the effectiveness of treatment more quickly.
The research team shared information on the Liquid Biopsy for Breast Cancer Methylation (LBx-BCM), as it’s called, in the journal Cancer Research Communications. LBx-BCM can work with a commercially available molecular testing platform called GeneXpert to detect the chemical tag methylation in one or more of nine genes altered in breast cancers. The sample can be taken in less that 15 minutes by a lab technician. The researchers say this simple and effective test could give oncologists an alternative to imaging to determine if chemotherapy is working. It could be particularly helpful for smaller tumors, as imaging isn’t as good at detecting changes in them.
Dr. Saraswati Sukumar, senior author and professor of oncology and pathology at the Johns Hopkins University School of Medicine, says, “Our goal was to develop an assay that would be sophisticated yet simple to perform worldwide and could be used at the point of care to provide same-day feedback to clinicians and patients. If we are able to show by this cartridge assay that we are indeed successful in predicting the course of treatment, we might be able to institute changes in the way we look at chemotherapy and the way we treat patients for metastatic breast cancer.”
The researchers had created a similar liquid biopsy laboratory assay that identified the presence of hypermethylation – or a chemical change in DNA that can inhibit genes that keep runaway cell growth in check – in 10 genes altered in breast cancers. When it’s detected in this test, that means there’s been a cancer recurrence or spread. The test, called cMethDNA, can detect up to 90% of patients with metastatic breast cancer. However, it takes up to 10 days to complete and requires more precision to administer. LBx-BCM was developed to take less time.
In their study of LBx-BCM, researchers had two people run the test on separate days, with samples from 11 patients with metastatic breast cancer and four without. Results were the same for more than 90% of the samples.
The team also tested the liquid biopsy on two sets of samples from prior Johns Hopkins studies. They looked into cumulative methylation of the nine genes in 20 samples from metastatic breast cancer patients and 20 patients without breast cancer. There was also a second set of samples from 40 metastatic breast cancer patients, 17 with benign breast disease, and nine without breast cancer. In both sets, LBx-BCM detected two to 200 times as much methylated DNA in samples from breast cancer patients than the samples from the others. The team says overall, the liquid biopsy accurately detected cancer 83% of the time and accurately ruled out cancer 92% of the time, which averaged out to a diagnostic accuracy of 85%.
If these findings are replicated, the hope going forward is that doctors can start using the test in patients to help determine the most effective treatments.
The study authors say, “Further prospective clinical trials will evaluate LBx-BCM’s detection sensitivity and its ability to monitor therapeutic response during treatment for advanced breast cancer.”