Researchers discover process that neutralizes tumors

Avatar By Tyler MacDonald | 2 years ago

A team of University of California San Diego researchers has discovered a unique mechanism that could help medical professionals determine if cancer patients will respond to immunotherapy.

The human body’s immune system ideally identifies tumors and sends its immune cells (T cells) to to find and destroy them. But tumor cells have evolved to employ a PD-L1 protein to prevent immune cells from working properly.

Although antibodies that benefit some cancer patients have been developed to prevent PD-L1/PD-1 , it’s remained a mystery why some patients don’t respond to these therapies. But the new study might have just revealed some clues.

The team discovered that some tumor cells display their PD-L1 weapon as well as a PD-1 “brake” that neutralizes tumors. This expression causes PD-1 to attach to and neutralize the PD-L1 located on the same cell.

“It’s a very exciting finding,” said Enfu Hui, co-author on the study. “Our study uncovered an unexpected role of PD-1 and another dimension of PD-1 regulation with important therapeutic implications.”

The team is hoping to extend the the finding to focus on immunotherapy and reveal other mechanisms of “self-cancellation” that work on the surface of immune and tumor cells.

“We think that our finding is the tip of the iceberg,” Hui said. “We speculate that self-cancellation is a general mechanism to regulate immune cell function. Understanding these processes more clearly will help develop better immunotherapy strategies and more reliably predict whether a patient will respond or not.”