Humans are individuals, but also an ecosystem.
Inside us, half of the cells belong to us, but the other half belongs to a multitude of bacteria that inhabit us.
These bacteria interact with our body, help us digest and even influence our mental state.
A different microbial composition has been observed in people with depression, and stool transplants have already been used to treat intestinal problems or antibiotic-resistant infections.
In recent years, new genome sequencing techniques have multiplied the knowledge of this microscopic ecosystem and the possibilities that its knowledge offers to medicine.
One of these latest applications is known as precision medicine, which seeks to offer each person tailored treatments.
In this field, the diagnosis and treatment of cancer, with its great variability and the importance of early detection, is of special interest.
This week, the journal Gut publishes the work of an international team of scientists showing that it is possible to detect the risk of pancreatic cancer early through an analysis of microbes found in feces.
The authors, led by Núria Malats, from the National Cancer Research Center (CNIO), in Madrid, and Peer Bork, from the European Molecular Biology Laboratory (EMBL, Heidelberg, Germany), found a molecular signature of 27 microorganisms in stool samples that could predict those patients at high risk of pancreatic ductal adenocarcinoma, the most common pancreatic cancer.
With this type of test, which will still require more tests to verify its reliability, it would be possible to combat a frequent problem with pancreatic cancer.
Although it is not as common as colon or breast cancer, the symptoms that herald it usually appear when it is too late to remove the tumor with surgery and its mortality is very high.
Stool analysis would be a non-invasive way to identify a greater part of the population at risk in order to detect their tumors when they are still curable.
"The idea is that this type of test can be done at the hospital level or even in primary care, in screening programs such as the fecal occult blood test for colon cancer," explains Malats.
This would help to better identify the population at risk of suffering from an unusual type of tumor.
"Genetic criteria are now used, identifying people with rare mutations that predispose to these tumors or seeing if there is a family history, but that only reaches 10% of cases," says the CNIO researcher.
"There are 90% of cases that are sporadic and it is necessary to define who are the high-risk individuals," she adds.
To identify the relationship between a particular microbiome and cancer risk, the authors of the paper published today studied the cases of 136 people: 57 people newly diagnosed with pancreatic cancer, 29 who had chronic pancreatitis and 50 who were controls. .
The patients, who came from the Ramón y Cajal hospital in Madrid and the Vall d'Hebron in Barcelona, had samples of saliva, feces and pancreatic tissue extracted to analyze their microbiota.
With these data, the authors still do not know if the presence of the tumor modified the bacterial ecosystem of the patients or if it was the microbial composition that predisposed them to develop cancer, but they suspect that the second option is more likely.
"The panel of 27 microorganisms is the same in advanced and initial tumors, so it could be that their presence indicates a predisposition, but these are still all assumptions," admits Malats.
The microbes found in the patients' stool were also in their tumors, and the authors want to further investigate this relationship to find out what role these bacteria play in the development of the disease.
Decades ago, the relationship between some viruses and the appearance of tumors was discovered, and the presence of a bacterium such as Helicobacter pylori is behind some types of cancer.
"In the coming months and years we are going to study the role of these bacteria in order to be able to intervene with probiotics or antibiotics," says the CNIO researcher.
Rafael Cantón, Head of the Clinical Microbiology Service at the Ramón y Cajal University Hospital in Madrid, who did not participate in the study, points out that “this type of analysis is not yet within the reach of all laboratories, but in the future they may be of interest. as biomarkers to improve the diagnosis of some pathologies, including pancreatic cancer”.
Those responsible for the work have already applied for a patent to develop a diagnostic kit that detects these microbial genomes in feces.
You can follow MATERIA on
,
and
, or sign up here to receive
our weekly newsletter
.
Exclusive content for subscribers
read without limits
subscribe
I'm already a subscriber