Scientists have discovered traces of the fungus hidden in the tumors of people with different types of cancer, including breast, colon, pancreatic and lung cancers.
However, it is still unclear whether these fungi play a role in the development or progression of cancer.
Two new studies, both published September 29 in the journal Celldiscovered DNA from fungal cells hiding in tumors throughout the body.
In one study, researchers looked for the genetic fingerprints of fungi in 35 different types of cancer by examining more than 17,000 tissue, blood and plasma samples from cancer patients.
Not all tumor tissue samples tested positive for fungi, but overall the team found fungi in all 35 cancer types assessed.
“Some tumors had no fungus at all, and some had a huge amount of fungus,” co-lead author Ravid Straussman, a cancer biologist at the Weizmann Institute of Science in Rehovot, Israel, told STAT. often, however, when the tumors contained fungi, they did so in “low abundance,” the team noted in their report.
Based on the amount of fungal DNA discovered by his team, Straussman estimated that some tumors contain one fungal cell for every 1,000 to 10,000 cancer cells.
If you consider that a small tumor can be loaded with around a billion cancer cells, you can imagine that mushrooms can “have a big effect on cancer biology,” he said.
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Straussman and his team found that each type of cancer tended to be associated with its own unique collection of fungal species; these included generally harmless fungi known to live in humans and some that can cause disease, such as yeast infections.
In turn, these fungal species often coexisted with particular bacteria within the tumor. For now, it is not known if and how these microbes interact in the tumor and if their interactions help fuel the spread of cancers.
The second Cell the study found similar results to the first but focused specifically on gastrointestinal, lung and breast tumors, Nature reported. The researchers found that each of these three types of cancer tended to harbor the fungal genera candidiasis, Blastomycesand Malasseziarespectively.
Both research groups have found clues that the growth of certain fungi may be linked to worsening cancer outcomes. For example, Straussman’s group discovered that breast cancer patients with the fungus Malassezia globosa in their tumors showed lower survival rates than patients whose tumors did not have the fungus.
The second group, led by immunologist Iliyan Iliev of Weill Cornell Medicine in New York, found that patients with a relatively high abundance of candidiasis in their gastrointestinal tumors showed increased gene activity linked to endemic inflammation, cancer spread and low survival rates, Nature reported.
Despite these early clues, none of the studies can say for sure if fungi actually cause these poor outcomes or if aggressive cancers simply create an environment where these fungi can easily grow.
The studies also don’t address whether mushrooms can contribute to the development of cancer, causing healthy cells to become cancerous.
Both studies have similar limitations. For example, tissue and blood samples were pulled from existing databases, and some samples may have been contaminated with fungi during the collection process, said Ami Bhatt, a microbiome specialist at the University. from Stanford, California. Nature.
Both research groups attempted to remove these contaminants, but even with these precautions, Bhatt said it would be best if the results could be replicated with samples taken in a sterile environment.
Straussman told STAT that these initial studies serve as a springboard for future research into the mycobiota, or communities of microbes associated with cancers.
“As a field, we need to assess everything we know about cancer,” he said. “Look at everything through the lens of the microbiome – the bacteria, the fungi, the tumors, even the viruses. There are all these creatures in the tumor, and they have to have an effect.”
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This article was originally published by Live Science. Read the original article here.