Pap test fluid used to detect ovarian and endometrial cancers
Washington: Scientists at the Johns Hopkins Kimmel Cancer Center have developed a test to detect ovarian and endometrial cancers using cervical fluid obtained during routine Pap tests.
In a pilot study, the "PapGene" test, which relies on genomic sequencing of cancer-specific mutations, accurately detected all 24 (100 percent) endometrial cancers and nine of 22 (41 percent) ovarian cancers.
The investigators note that larger scale studies are needed before clinical implementation can begin, but they believe that the test has the potential to pioneer genomic-based cancer screening tests.
The Papanicolaou (Pap) test, during which cells collected from the cervix are examined for microscopic signs of cancer, is widely and successfully used to screen for cervical cancers.
However, no routine screening method is available for ovarian or endometrial cancers.
Since the Pap test occasionally contains cells shed from the ovaries or endometrium, cancer cells arising from these organs could be present in the fluid as well, Luis Diaz, MD, associate professor of oncology at Johns Hopkins and director of the Swim Across America Laboratory said.
"Our genomic sequencing approach may offer the potential to detect these cancer cells in a scalable and cost effective way," Diaz added.
Cervical fluid of patients with gynecologic cancer carries normal cellular DNA mixed together with DNA from cancer cells, according to the investigators.
Their task was to use genomic sequencing to distinguish cancerous from normal DNA.
The scientists had to determine the most common genetic changes in ovarian and endometrial cancers in order to prioritize which genomic regions to include in their test.
From the ovarian and endometrial cancer genome data, the Johns Hopkins-led team identified 12 of the most frequently mutated genes in both cancers and developed the PapGene test with this insight in mind.
The investigators then applied PapGene on Pap test samples from ovarian and endometrial cancer patients at The Johns Hopkins Hospital, Memorial Sloan-Kettering Cancer Center, the University of Sao Paulo in Brazil and ILSBio, a tissue bank.
The new test detected both early and late stage disease in the endometrial and ovarian cancers tested.
The findings are published in the journal, Science Translational Medicine.