Pilot study of five-hour molecular test accurately distinguishes malignant and benign breast tumours
A team led by Johns Hopkins Kimmel Cancer Center investigators reports that a new laboratory test they developed to identify chemical changes to a group of cancer-related genes can accurately detect which breast tumours are cancerous or benign, and do it in far less time than gold-standard tests on biopsied breast tissue.
Although the findings are preliminary and need further validation in larger groups of people, the investigators say the test has the potential to dramatically reduce the time (minimum by one month, maximum by 15 months) generally needed to make a definitive breast cancer diagnosis in poorer countries. A quick diagnosis has already been definitively proven to boost survival for all cancers by reducing wait times to surgical and other treatments. A report on the test, which exploits the tendency of some cancer-related genes to undergo the attachment of a chemical group, by a process known as methylation, has been published.
“Diagnosis is a huge bottleneck to starting treatment, especially in developing countries that have a small number of pathologists available to review breast cancer biopsies who serve a huge population,” says study leader Saraswati Sukumar, Ph.D., professor of oncology and pathology at the Johns Hopkins Kimmel Cancer Center. “That means a test like ours could be especially useful in places with fewer resources and where mortality rates from breast cancer are much higher compared to the developed world.”
Breast cancer cases are rising around the world, Sukumar notes. Globally, breast cancer incidence is steadily increasing. In 1980, GLOBOCAN reported 641,000 new cases of breast cancer worldwide. In 2018, the estimated incidence of breast cancer worldwide rose to 2.1 million cases (a 3.2% annual rate of increase) with 626,000 deaths due to this cancer.
The reasons for higher death rates in the developing world include social stigmas that prevents many women from seeking timely treatment and a lack of healthcare resources. However, a major factor is time between biopsies and delivery of a diagnosis, which can be as long as 15 months in places with fewer resources compared to a few days or weeks in the United States.
Seeking to shrink the time from biopsy to diagnosis, Sukumar and her colleagues in the Johns Hopkins Kimmel Cancer Center, Johns Hopkins University School of Medicine’s departments of pathology, surgery, and radiology, and the Johns Hopkins Bloomberg School of Public Health and collaborators from Cepheid developed a novel technology platform. Here, a patient’s biopsy sample is loaded into cartridges and inserted in a machine that tests levels of gene methylation—a chemical addition to genes that results in changes in gene activity. This platform returns methylation marker results within five hours.
These results suggest that the test holds promise as a “first pass” to distinguish between malignant and benign breast tumours, Sukumar says. With the 5-hour-long return on results, low skill required to run the test, and relatively low expense, it could offer hope of speeding diagnosis for thousands of women worldwide.
Sukumar cautions that the team’s molecular test cannot replace expert analysis by a pathologist, whose skill will be necessary to review core biopsies of the breast lesion for a definitive diagnosis and optimal therapy recommendations.
John Hopkins University