In 2019, a team of researchers from New York University School of Medicine reported, in the journal Naturethat a fungus called Malassezia globosa is associated with the progression of pancreatic cancer. It is likely that this fungus migrates there from the intestinal contents.
It has been shown that Malassezia activates the “complement” cascade, a system of immunity made up of about thirty proteins present in the plasma. The complement participates in the inflammatory reaction, involved in the cancerous process. In pancreatic cancer, the activation of complement by the mycobiota induces an immunosuppressive environment within the tumor, in other words a permissive environment that tolerates the presence of cancer cells.
Chemotherapy improvement
In mice with pancreatic cancer, the disappearance of the mycobiota following administration of an antifungal treatment leads to significant tumor regression. In addition, it turns out that the ablation of the mycobiota increases the activity of gemcitabine, a chemotherapy drug commonly used in patients suffering from pancreatic cancer.
Finally, in a study published in the journal Cancer Cell in February 2022, researchers from the Roswell Park Comprehensive Cancer Center, in Buffalo (United States), indicated that the expression of the inflammatory molecule interleukin-33 (IL-33 ), the secretion of which is dependent on the presence of fungi within the tumours. IL-33 makes it possible to attract immune cells into the tumor that are tolerant to the presence of tumor cells and which secrete molecules that stimulate tumor growth.
It remains to be determined whether living fungal cells, or only some of their components, are at the origin of these mechanisms. It is unknown whether those induced by pancreatic mycobiota are also at work in other cancers.