Innovation

Down Syndrome NIPT (Noninvasive Prenatal Testing) Also Detects Maternal Cancers

NIPT
Non-invasive prenatal testing not only identifies fetuses with Down syndrome, it also can detect maternal cancers at an early stage, before symptoms even appear. Photo courtesy of Shutterstock.

Increasingly, doctors rely on non-invasive prenatal testing (NIPT) when checking for fetal disorders, including Down syndrome. Importantly, NIPT does not carry the risk of miscarriage involved in invasive testing methods, such as amniocentesis. Researchers recently discovered another surprising advantage of NIPT — it can detect maternal cancers at an early stage, before symptoms even appear.

From an expectant mother’s point of view, NIPT could not be easier. All that is involved is a simple blood draw and then the results come back in about a week. Though an NIPT can be done any time after 10 weeks, doctors usually perform the test between 10 and 22 weeks. The basis for the test is the fact that DNA from a fetus circulates in the mother’s blood. Only about 10 to 15 percent of the DNA circulating is from the fetus, but it can still be detected and measured.

Most importantly, scientists can distinguish fetuses affected with Down syndrome (also called trisomy 21), and a few other fetal aneuplodies — the presence of an abnormal number of chromosomes in a cell. Down syndrome is the most frequent chromosomal abnormality, occurring in about one in 700 babies. As a mother ages, the possibility she will give birth to a baby with Down increases, with this risk rising sharply beginning at age 36.

In fact, it was Down and not cancer that was on the minds of the researchers of the current study. They set out to improve the accuracy of the NIPT in detecting this syndrome.

Accidental Discovery

“Even though it is very reliable, we believed that we could make it even better, and in doing so we could also find other chromosomal abnormalities apart from the traditional trisomy syndromes — Down's, Edward's (trisomy 18), and Patau (trisomy 13),” Dr. Nathalie Brison, a senior scientist at the Centre for Human Genetics, UZ Leuven, Belgium, stated in a press release.

In a trial run of a new version of NIPT, then, Brison and her colleagues looked at chromosomes circulating in maternal blood for over 6,000 pregnancies. With three women, they were surprised to identify genomic abnormalities. Yet, these abnormalities could not be linked to either the mother or the fetus and they also bore a resemblance to cancer. Immediately, the researchers referred the three women to the oncology unit.

Following an MRI scan and other tests, the women wilted as they sadly listened to their doctors delivering a diagnosis of early stage cancer.

Without NIPT these three instances of cancer would have been unlikely to have been detected until they became symptomatic — a much later stage, one more difficult to treat. Importantly, the NIPT chromosome profile normalized in these three women following treatment. The researchers say this indicates NIPT can measure response to treatment and might do so after the very first chemotherapy treatment.

Not Just For Pregnant Women

While this research is wonderful news for expectant mothers, it also might be applied to the general population, offering a non-invasive way of detecting pre-symptomatic cancers. Large-scale studies would have to be conducted first to confirm these results. However, the researchers feel confident NIPT could become an effective, non-invasive cancer screening tool for one and all.

“We now know that it is possible to offer the accurate detection of chromosomally imbalanced cancers to the general population via minimally invasive screening methods,” Brison said. While the ethics of peering into someone’s genetic code continues to be debated, this research offers a glimpse of what’s to come in medicine.

Source: Amant F, Verheecke M, Wlodarska I, et al. Presymptomatic Identification of Cancers in Pregnant Women During Noninvasive Prenatal Testing. JAMA Oncology. 2015.

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