DNA traces of viruses and bacteria in the blood could provide clues as to whether a person has cancer. An international team of researchers with the participation of bioinformaticians from the University of Gießen has shown this. The scientists used artificial intelligence to find out whether the presence of certain microbes is indicative of tumors. To do this, they analyzed more than 18,000 samples from around 10,500 patients with 33 different types of cancer.
The researchers had expected some relationships, for example, that human papillomaviruses are associated with cervical, head and neck cancer and Fusobacterium species with gastrointestinal cancer. The team also found previously unknown microbial signatures that make it possible to differentiate between different types of cancer. The presence of Faecalibacterium species differentiates colon cancer from other tumors. Epstein-Barr virus DNA fragments, in turn, suggest various types of gastric cancer.
Several companies are working on blood tests to diagnose cancer that can be used to detect changes in human DNA. “A test based on microbial DNA should be much easier,” says Giessen bioinformatics specialist Stefan Janssen. Further large studies should show whether every cancer can be identified with this method.