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Genetic predisposition influences cancer development
The human body is full of bacteria. Whether in the mouth, on the hands or in the intestines. Without the tiny organisms, human survival would certainly not be possible. Over time, the human body has adapted and adjusted to the dangers.
Not only have human genes changed in the course of evolution, the pathogens of various diseases have also adapted to changes in the human body. A connection between the evolution of the genome in humans and bacteria could apparently be demonstrated and with it the susceptibility to infection and its strength.
This is what the US researcher Babara Schneider and her team want to find out in studies of people who carry the so-called “Helicobacter pylori” bacterium (HP). The researchers published their results in the journal "PNAS". This pathogen is instrumental in the development of stomach cancer, inflammation of the gastric mucus and gastric ulcers and is found on and within the lining of the stomach.
People around the world carry it, but only a fraction of those infected develop serious complaints. For their investigations, the scientists then examined the genetic makeup of people from two areas in Colombia. The researchers were particularly interested in the distribution and variants of HP bacteria, because gastric cancer is much more common in mountainous areas in Central America than in coastal regions. Here, in the course of the colonization of the continent by the predominantly Spanish occupiers, a European variant of the bacterium developed.
The researchers were able to prove that the strains of the pathogen have adapted to varying degrees to the human organism on different continents in the course of evolution. It was found in people of Indian origin that the African branch of the HP bacterium causes precursors of cancer more often than in people with African roots. This fact leads the scientists to the conclusion that the African variant has developed further with the African population and has lost its aggressiveness. Bacteria in which European shares dominated, on the other hand, had not developed further with humans and were therefore probably more aggressive. (fr)
Image: Angela Bausch / pixelio.de