Humans carry a lot of bacteria in and on our bodies, called our microbiome. Estimates about the number of microbes in the human body have varied, but it’s clear we have at least one bacterial cell for every human cell; that also means we have far more bacterial genes in our body than we do human genes. These microbes play an important role in health, one that is growing ever-larger as research into the role of microbes in human health expands. Now scientists have turned their attention toward learning more about how microbes influence cancer growth.
A special issue of the journal ecancermedicalscience has focused on what has been termed the oncomicrobiome. A variety of articles will be presented that review findings in several areas. Learn more from the video.
"Humans are super-organisms of massive interconnecting genomes from trillions of organisms that are all essential for maintaining health," said Guest Editor Dr. Alasdair Scott of Imperial College, London, UK. “We're beginning to appreciate that the human microbiome impacts on nearly every aspect of human physiology and pathophysiology," Scott added.
It seems that from the beginnings of human evolution, the microbes we carry have been evolving right along with us, and have become vital to some aspects of our physiology. It would not be a stretch to think that these microbes are also related to the development of cancer.
"This cutting-edge Special Issue delves into our rapidly evolving understanding of the microbiome in both the causation and treatment of cancer," said Scott.
There are six review articles in the issue, which focuses on various aspects of the links between the microbiome and cancer. The microbiome is considered from the standpoint of lung cancer, and from colorectal cancer. Colorectal cancer is thought to have a lot to do with environmental influences as well as the bacterial species in the gut. Certain bacteria, like Fusobacterium nucleatum, and Escherichia coli, are more prevalent in patients. Meanwhile, in the lungs, it's also been shown that shifts in the bacterial composition of the lung microbiome are correlated with cancer development.
Scientists are also beginning to characterize various strains of bacteria with respect to their association with tumors. Instead of considering microbes as individuals, the entire community is taken into account; we know now that the microbiome has to be considered as a whole.
Researchers have taken note of some of the inadvertent ways in which microbes may be contributing to cancer. For example, some intestinal bacteria can make chemicals like phenol, hydrogen sulfide, or proteases; the former can do damage to DNA, the latter can increase inflammation, which can increase the risk of cancer.
The interaction of the microbiome with chemotherapy is also considered as an aspect of pharmacobiomics - the therapeutic potential of pre and postbiotics; these therapies may be useful for cancer patients. In that review, the authors compile some of the various findings in the area, but warn that the field is still in its infancy.