According to researchers at Medical College of Georgia, IDO, an enzyme that works like a firefighter to keep inflammation under control, can be captured to protect early malignant cells
"Inflammation should really help prevent a tumour. You want a good immune response; this is what protects you from pathogens," he says. "In this case, it's an unfortunate exploitation by malignant cells," says Dr. Andrew Mellor, director of the MCG Immunotherapy Center and Georgia Research Alliance Eminent Scholar in Molecular Immunogenetics.
In fact, the researchers found strong evidence that inflammation triggers the immune response.
In the study, the researchers gave mice a single dose of a carcinogen right at the moment when they started painting a tiny portion of skin with a poison ivy derivative twice weekly for 20 weeks.
The mix quickly produced IDO and created a "suppressive" immune response that helped resulting precancerous cells grow into tumors. However, employing the same protocol in a mouse in which IDO had been genetically deleted, dramatically slowed tumour development.
The significance of the new study is that the researchers have shown that IDO, or indoleomine 2,3-dioxygenase, may be produced as a part of the inflammatory mix, which could then protect the malignant skin cells.
"'Chronic' is the key word. We have long suspected that IDO is a component of certain kinds of inflammation that create suppression," said Mellor.
He speculated that IDO's "firefighter" role probably resulted from the body's need to control inflammation in areas such as the gastrointestinal tract. The GI tract is constantly bombarded by food and microbes which could lead to debilitating and deadly inflammation.
The new research, according to Mellor, showed that IDO has a more important and earlier role than we thought in tumor formation.
"IDO favors the tumor: The immune system basically sits back and watches the tumor grow," said Mellor.
The study is published online in Proceedings of the National Academy of Sciences.