02/04/2020
*Scientific proof
New blood test can detect 50 types of cancer
The Guardian
System uses machine learning to offer new way to screen for hard-to-detect cancers
Pancreatic cancer cells. The AI-based system detected 63% of stage I pancreatic cancers, and 100% at stage IV in the study. Photograph: Stocktrek Images, Inc./Alamy Stock Photo
A new blood test that can detect more than 50 types of cancer has been revealed by researchers in the latest study to offer hope for early detection.
The test is based on DNA that is shed by tumours and found circulating in the blood. More specifically, it focuses on chemical changes to this DNA, known as methylation patterns.
Researchers say the test can not only tell whether someone has cancer, but can also shed light on the type of cancer they have.
Dr Geoffrey Oxnard of Boston’s Dana-Farber Cancer Institute, part of Harvard Medical School, said the test was now being explored in clinical trials. “You need to use a test like this in an independent group at risk of cancer to actually show that you can find the cancers, and figure out what to do about it when you find them,” he said.
Writing in the journal Annals of Oncology, the team reveal how the test was developed using a machine learning algorithm – a type of artificial intelligence. Such systems pick up on patterns within data and as a result learn to classify it.
The team initially fed the system with data on methylation patterns in DNA from within blood samples taken from more than 2,800 patients, before further training it with data from 3,052 participants, 1,531 of whom had cancer and 1,521 of whom did not.
Using this information, the system sorted the samples into groups based on the methylation patterns. The team then taught the system which groups reflected which type of cancer.
“In pregnant women we look in their free-floating DNA for foetal abnormalities,” said Oxnard. “We know this [approach] exists, the question is how do you fine-tune and perfect the art of lo