A study published in Nature found that the movement of certain fungi from the gut to the pancreas can increase the risk of cancer by up to a thousand-fold. The study provides strong evidence that the mycobiome can turn normal cells into pancreatic ductal adenocarcinoma (PDA)—a particularly deadly form of pancreatic cancer.
Researchers assessed mice and patients with pancreatic cancer and observed that fungal species travel into the pancreas up the pancreatic duct.
Antifungal drugs reduce tumor weight
The researchers performed analyses over 30 weeks of fecal samples from mice with and without pancreatic cancer. They observed significant differences in the size and composition of the fungal population in the cancerous pancreas compared with a healthy one. The largest population increase in both mice and human tissue was seen in the genus Malassezia, which includes 14 species. There were also abnormally higher numbers in the genera Parastagonospora, Saccharomyces, and Septoriella.
“We have long known that Malassezia fungi—generally found on the skin and scalp—are responsible for dandruff and some forms of eczema, but recent studies have also linked them to skin and colorectal cancer,” said senior coauthor Deepak Saxena, PhD, professor of Basic Science and Craniofacial Biology at New York University College of Dentistry, in a press release. “Our new findings add evidence that Malassezia is abundant in pancreatic tumors as well.”
The researchers also found that treating mice with amphotericin B, an antifungal drug, reduced their PDA tumor weight by 20% to 40% over the 30 weeks. Once the murine pancreases were mostly cleared of fungi following treatment, the researchers assessed the effect on cancer growth for specific types of fungus. Cancer grew 20% faster in the pancreases of mice repopulated with Malassezia, but not in the presence of other common fungal species.