Microscopic fungus may have more to do with oral cancer and ageing than initially thought, according to new research from Case Western Reserve University, United States. Researchers from the School of Dental Medicine, Case Comprehensive Cancer Center and School of Medicine are hoping a new study can lead to a medical breakthrough in understanding certain types of oral cancer.
Pushpa Pandiyan, an associate professor of biological sciences at the dental school, led a team of local researchers studying the function of specific T cells, known as Tregs, during the development of oral cancer in ageing mucosa — the moist inner lining of some organs and body cavities, such as the nose, mouth and lungs.
“We think this is the beginning of something important and monumental,” she said. Their findings recently appeared in Frontiers in Oncology.
Pandiyan and the researchers examined the role of dectin-1 — a cell’s pattern-recognition and immune receptor — and its ability to trigger an inflammatory response that resists fungal infection. Dectin-1 is among the fungi receptors that expresses on a host cell.
Typically, human white blood cells have regulatory (Tregs) and myeloid derived suppressor cells, which curb the immune responses of cancer-fighting immune cells. Problems occur, Pandiyan said, when these cells accumulate during tumour growth.
“What we’re finding now is that the dectin-1 receptor, usually responsible for anti-fungal immunity, is now responsible for accumulation of these cells at excessive levels in tumours,” she said.
Researchers pointed out that the culprit is likely the result of immune cells somehow overreacting to fungal microbiota. Although dectin in normal levels serves as a protective measure, Pushpa said excessive amounts can promote tumour growth “because of its ability to recruit immunosuppressive cells”.
“Accumulation of these cells were much worse during ageing,” Pandiyan said, adding that the findings may relate to ageing. “Our bodies produce more dectin-1 the older that we get. In other words, anti-tumour defence mechanisms are weakened with age.”
While the research was limited to studying ageing oral mucosa, Pandiyan said the findings may have broader implications for additional cancer research: “We don’t know about other cancers yet, but in oral cancers, if there is dectin-1, there’s a better chance that anti-tumour cells can be staved off.”
The research was funded by the Case Comprehensive Cancer Center’s Specialized Program of Research Excellence (SPORE) pilot programme, and their findings recently appeared in Frontiers in Oncology.
Other researchers involved in the work include: Natarajan Bhaskaran, Sangeetha Jayaraman, Cheriese Quigley and Prerna Mamileti from the School of Dental Medicine; Mahmoud Ghannoum and Quinton Pan, from the School of Medicine; Aaron Weinberg, from the dental school and Case Comprehensive Cancer Center; and Jason Thuener from the Case Comprehensive Cancer Center.