How do glioblastomas disappear from the immune system?

All cancer cells are harmful, but few behave as aggressively and invasively as those that make up glioblastoma, a form of brain cancer. New research now provides clues to how glioblastoma cells hide from the body’s immune system, giving scientists hope that the ideas could lead to more accurate diagnoses and better treatment options.

Like all cancers, glioblastomas are the same cells of the body that have mutated and turned treacherous, taking over areas of the brain in a sudden, rapid incursion. They grow rapidly, create multiple mutations, signaling pathways, and recruit healthy cells as reinforcements. Once these cells become established, they are often difficult to find or eliminate. Surgery may work temporarily, but because these tumors are made of glial cells (a type of cell found in the central nervous system), they often hide within brain tissue and out of the surgeon’s reach. Chemotherapy, radiation, and some targeted therapies are usually used to try to stop or slow the invasion.

What are glioblastomas?

Glioblastoma is a grade IV version of a glioma, a tumor of the brain, brain stem, or central nervous system. Tumors usually present a number of symptoms, including headache, dizziness or nausea, difficulty seeing or speaking, and/or seizures. These tumors are sometimes called astrocytomas, relative to the star-shaped glial cells called stellate cells of which they are composed. Researchers have yet to determine how and why glioblastoma forms. “Some of them start out strong and keep growing,” says Laura Farrington, MD, a medical oncologist at our hospital near Chicago. “Some of them start out as benign tumors. And over the years, they acquire more mutations that make them more aggressive.” Some recent studies have shed new light on how and why these rogue cells become so twisted and destructive.

Researchers in Sweden believe they have discovered a way for glioblastoma to bypass the immune system. In the results of a study published this year, scientists concluded that glioblastoma cells create a signaling pathway to communicate with microglia, the immune cells in the brain. The signal tricks microglia into blocking a normal protective protein, leading to “stimulating cancer cells rather than attacking them,” said Bertrand Joseph, the study’s lead author. Everyday science . In fact, glioblastomas have sometimes been found to be loaded with immune cells, according to an article published this year by the Journal of Clinical Research.. But as with many cancer cells, glioblastoma cells find ways to recruit, avoid, or make less effective immune cells. Immunotherapy, a promising treatment that stimulates immune cells against a variety of cancers, has not yet been shown to be useful against glioblastomas.

How is glioblastoma treated?

“The challenge in treating glioblastoma is that there are so many cellular mutations and so many pathways,” says Dr. Farrington. “You can try one path and kill some cells, but then they find a way to beat it. Cancer is smart. Cancer is the cells in your body that just went crazy and learned how to grow and grow.” But more mutations also mean more opportunities to target glioblastomas with information from advanced genomic testing. The tests are used to screen tumors at the molecular level and identify specific mutations that could lead to more specific treatments. “In many other cancers, we have genetic mutations that cannot be attacked, at least not at the moment,” says Dr. Farrington. “In glioblastoma, we have multiple mutations that we can attack and treat. But these tumors have a lot of mutations, so we can treat some of them, but 12 of them are difficult to treat at the same time. This is what makes the treatment so. Difficult . “

Oncologists also have difficulty determining the long-term prognosis for patients with glioblastoma due to the unpredictable nature of the cancer’s aggressiveness. In search of more clues, Johns Hopkins Medicine researchers have developed what they call a cellular “race pathway” that allows them to determine how quickly a glioblastoma cell travels. Preliminary results indicate that the faster the cell, the more aggressive the tumor. Dr. Alfredo Quinones-Hinojosa of Johns Hopkins University School of Medicine suggests that these tests may one day lead to more accurate diagnoses and “provide useful updates, inform treatment options, and possibly develop new treatments faster.”

In the search for better treatments and prevention strategies, scientists are learning more about how cancer grows and survives, even in the harshest environments. This blog is part of an occasional series called How Does Cancer Do It? Designed to highlight recently discovered cancer-related behaviors that add to our growing understanding.

Learn more about glioblastoma, its symptoms, and the treatments used to combat it.