The non-invasive prenatal test (NIPT), developed to detect Down syndrome and other chromosomal abnormalities in unborn children, can also detect blood cancers. Not just in pregnant women but in everyone. This is because the test examines the DNA that is circulating in the blood - and that may include the genetic material of cancer cells.
NIPT is a prenatal blood test designed to detect chromosomal abnormalities in the foetus. The test can easily be run on a pregnant woman’s blood sample, as the mother’s blood also contains tiny bits and pieces of the baby’s DNA.
In the past couple of years, eight pregnant women who underwent the NIPT were diagnosed with cancer by mere chance. Their cancers were discovered by the Centre for Human Genetics (CME) at University Hospitals Leuven. First, the results of the mothers’ NIPT came back abnormal. A closer examination then revealed that these anomalous results were not due to chromosomal abnormalities in the foetus but due to cancer in the mother. After all, the DNA of many tumours also circulates in the blood.
That gave researchers the idea to use the NIPT for cancer screening in healthy subjects. In a large-scale study, led by Professor Joris Vermeesch (CME), Professor Frédéric Amant and Dr Liesbeth Lenaerts from the Gynaecological Oncology Unit at KU Leuven, blood samples were collected from 1,002 patients over the age of 65. The researchers examined these samples for the presence of genetic material that could point to a developing tumour.
A small number of people were diagnosed with blood cancer, explains Dr Liesbeth Lenaerts: "We diagnosed five patients with Hodgkin’s disease or non-Hodgkin lymphoma. A sixth patient was diagnosed with a precursor stage that is associated with an increased risk of developing a type of blood cancer later in life. In 24 other test subjects, we found genetic defects in their blood, but no cancer. These people will be monitored to find out whether they’ll develop cancer at a later stage."
A number of small-scale studies had already shown that the NIPT can detect the DNA of Hodgkin lymphoma circulating in the bloodstream. These studies involved patients who had already been diagnosed before undergoing the NIPT. The current study is unique because the researchers succeeded in using the NIPT to diagnose cancer in supposedly healthy patients - in other words, before symptoms start showing. Further research will have to show whether the test may be used on a large scale to screen healthy people - for instance those with an increased risk - for blood cancers in an early stage, and also whether the test may be adapted to screen for other types of cancer as well.