Ovarian cancer has long been one of the trickiest forms of cancer to diagnose and treat. It often goes unnoticed until the late stages. For most women, the cancer goes into remission after the first round of treatment but then returns with a vengeance. Three-quarters of the time, ovarian cancer comes back with a tumor that stubbornly resists chemotherapy.
Now, investigators at the Center for Individualized Medicine at Mayo Clinic have new hope for improving the odds against ovarian cancer. They’ve found a new way to catch it when it returns --potentially as soon as right after surgery.
New research from George Vasmatzis, Ph.D., of the Department of Laboratory Medicine and Pathology at Mayo Clinic, finds liquid biopsies from blood tests and DNA sequencing can detect a return of ovarian cancer long before a tumor reappears. That could lead to earlier intervention and more effective, individualized treatment. Dr. Vasmatzis’ research on the “Quantification of Somatic Chromosomal Rearrangements in Circulating Cell-free DNA From Ovarian Cancers” is published in the July 20 edition of Scientific Reports.
“With liquid biopsies, we don’t have to wait for tumor growth to get a DNA sample,” says Dr. Vasmatzis. “This important discovery makes it possible for us to detect recurrence of the disease earlier than other diagnostic methods. We can repeat liquid biopsies to monitor the progression of the cancer. That gives hope of a better treatment plan over time.”
The study was conducted with 10 patients in advanced stages of ovarian cancer. Blood was drawn before and after surgery. Investigators compared DNA from the liquid blood biopsies to DNA tissue samples from the tumor, using mate-pair sequencing — an inexpensive whole exome sequencing that can reveal genetic changes that contribute to tumor growth.
“In this study, the blood drawn before and after surgery and the surgical tissue was used to identify DNA fragments with abnormal junctions that can only be seen in this patient’s tumor DNA,” explains Dr. Vasmatzis. “Next-generation mate-pair sequencing was used to identify specific DNA changes of the tumor to create an individualized monitoring panel for liquid biopsy. This allows us to shape treatment to the individual patient rather than using a standard treatment that may not work for everyone.”
When post-surgery DNA matched that of the tumor, patients were later found to have had a recurrence of ovarian cancer. However, when the post-surgery DNA did not match the DNA of the tumor, patients were found to be in remission.
In 2015, more than 21,000 women in the U.S. were diagnosed with ovarian cancer, and 14,000 women died of the disease.
Additional authors on the research team ─ all of Mayo Clinic ─ are:
This work was supported by the Mayo Clinic Center for Individualized Medicine, the Fred C. and Katherine B. Andersen Foundation and the Mayo Clinic Ovarian Cancer Specialized Programs of Research Excellence, P50 CA 136393. Francesco Multinu is a research fellow supported by the University of Cagliari in Italy.
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Tags: center for individualized medicine, diagnostic, Dr. George Vasmatzis, early detection for ovarian cancer, Liquid biopsy, mate-pair sequencing, mayo clinic, medical research, ovarian cancer, Uncategorized, whole genome sequencing