New blood DNA analysis can detect early-stage cancer

An American study published in Science Translational Medicine, which followed 200 cancer patients in the U.S., Denmark and the Netherlands, has paved the way for the early detection of several types of cancer in apparently healthy subjects. That could help people avoid the aggressive treatments required by the later, metastasized stages of the disease.

Using a new blood test, researchers at Johns Hopkins Kimmel Cancer Center in Baltimore in the U.S. were able to successfully diagnose, in 62 percent of cases, stage 1 and stage 2 cancers among 138 patients suffering from colorectal, breast, lung and ovarian cancer.

The most promising results concerned ovarian cancer, with 67 percent detected at stage 1 and 75 percent at stage 2 of the disease.

The effectiveness of the test for lung cancer, the most common cause of cancer-related death, was also encouraging: of the 71 patients in the study affected by lung cancer, 45 percent were correctly diagnosed at stage 1 and 72 percent at stage 2 of the disease.

Colorectal cancer was detected among 89 percent of affected patients at stage 2, and among 50 percent of those affected at stage 1.

The screening approach used by the study is based on a new technique called targeted error correction sequencing (TEC-Seq) that allows ultrasensitive direct evaluation of sequence changes in plasma DNA using machinery that reads each chemical code in DNA 30,000 times.

A new type of blood test

“The challenge was to develop a blood test that could predict the probable presence of cancer without knowing the genetic mutations present in a person’s tumor,” said Victor Velculescu, Professor of Oncology at the Johns Hopkins Kimmel Cancer Center.

The new research is reminiscent of the work of French oncologist Patrizia Paterlini-Bréchot, at the Faculté de Médecine Necker-Enfants Malades, who has developed a blood test — which currently retails at €486 — that allows the early detection of all types of cancer without recourse to DNA analysis.

The French test, christened ISET (“Isolation by size of epithelial tumor cells”), can reveal the presence of tumour cells, which are bigger than healthy blood cells, in a 10ml blood sample, or among 50 billion red blood cells and 50 to 100 million white blood cells.

According to the American researchers who developed the new TEC-Seq technique, in the future, DNA testing could be used for population groups that have a high risk of cancer, smokers at risk of lung cancer, and women with hereditary mutations of the BRCA1 and BRCA2 genes that make them vulnerable to breast and ovarian cancer.

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Photo credit: SinobadZ/

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