Diagnosis of cancer by bacterial DNA
The simplest and most reliable method of detecting cancer at an early stage has been discovered
Sergey Kolenov, Hi-tech+
American researchers have found that dozens of different types of cancer correspond to unique "signatures" of bacterial DNA circulating in the blood. This can become the basis for a simple diagnostic test to detect the disease at the earliest stages. But first you need to understand what exactly binds bacteria to tumors.
One of the most promising areas in modern medicine is the development of a simple and reliable blood test to detect cancer at an early stage. It is proposed to use various molecules as biomarkers, from proteins to freely circulating tumor DNA.
An original approach to solving this problem was presented by specialists from the University of California at San Diego. Scientists, whose work is described in the press release Microbial DNA in Patient Blood May be Tell-Tale Sign of Cancer, found bacterial "signatures" in blood samples corresponding to dozens of different types of cancer.
Article by Poore et al. Microbiome analyses of blood and tissues suggest cancer diagnostic approach published in the journal Nature – VM.
At the first stage of the study, the team refuted the traditional idea that cancerous tumors are sterile. After analyzing more than 18,000 samples of tumor tissue belonging to 33 types of cancer, the authors found numerous traces of bacterial DNA. For each type of cancer, the bacterial "signature" was unique.
A specially created algorithm has learned to compare data on microbial DNA in the blood with a particular type of cancer. He continued to produce accurate results, even when samples associated with tumors in the third and fourth stages were excluded from the sample. This suggests that bacterial "signatures" are present in the blood of patients already at the early stages of the development of the disease.
To confirm the results obtained, the authors tested the technique on plasma samples of patients with prostate, lung and skin cancer. The results were very encouraging.
The algorithm accurately diagnosed lung cancer in 86% of cases and did not give a single false positive in the control group. In addition, the technique distinguished prostate cancer from lung cancer with 81% accuracy.
So far, scientists can't say exactly how bacteria and cancer are related. For example, it is unclear whether microorganisms live on the surface of tumors or inside them and how they affect the development of the disease. This means that the analysis of bacterial "signatures" will not soon become the basis for diagnostic tests. However, when this happens, doctors will have an excellent tool for detecting the early stages of cancer.
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