In a groundbreaking study, scientists at Karolinska Institutet have discovered that specialized immune cells can remember and attack ovarian cancer cells—offering new hope for powerful, personalized immunotherapies.
Key Points at a Glance
- Adaptive natural killer (aNK) cells can “remember” ovarian tumor signals
- These immune cells infiltrate tumors and intensify their attack upon re-exposure
- The discovery overturns the long-held belief that NK cells lack memory functions
- The research opens doors to new cancer immunotherapy approaches targeting ovarian cancer
The immune system is full of unsung heroes, but one type of white blood cell—once considered a blunt instrument—may actually be a master tactician. In a study published by researchers at Karolinska Institutet, a special subtype of natural killer cells, known as adaptive NK (aNK) cells, has been found to possess a remarkable ability to remember and respond aggressively to ovarian cancer cells.
Natural killer (NK) cells are often described as the immune system’s frontline defenders. Unlike T-cells, which require prior activation, NK cells patrol the body, ready to destroy infected or cancerous cells without needing to be “primed.” Until now, they were believed to act with innate but nonspecific aggression, lacking the sophisticated memory seen in other immune cells. This new research upends that assumption.
Led by Dhifaf Sarhan, senior lecturer in the Department of Laboratory Medicine at Karolinska Institutet, the study delves into the power of aNK cells—an elite subgroup of NK cells that can remember specific threats, including tumor cells. The researchers demonstrated that aNK cells not only recognize previous tumor signals but also respond more vigorously upon re-encountering them. This “memory-like” behavior allows aNK cells to mount a stronger, faster, and more targeted attack.
Using advanced single-cell RNA sequencing and gene expression mapping, the team studied aNK cell behavior in human ovarian tumor samples. Their findings were clear: aNK cells infiltrate tumors, retain memory of cancer-specific antigens, and actively collaborate with other immune cells to increase their cancer-fighting effectiveness. Far from being lone agents of destruction, these cells are both intelligent and cooperative.
“This completely reshapes our view of NK cells,” Sarhan explained. “It was once assumed that they were purely innate—powerful, but non-specific. Now, we know they have adaptive capabilities that can be harnessed for cancer therapy.”
The implications are profound. Ovarian cancer is notoriously difficult to treat, often diagnosed at an advanced stage and resistant to conventional therapies. With the discovery of aNK cells’ ability to recognize and recall tumor markers, researchers now have a new avenue to develop more precise and lasting immunotherapies.
Sarhan and her team are now focusing on the next phase: figuring out how to boost the number and potency of aNK cells in cancer patients. If successful, future clinical trials could explore how engineered or stimulated aNK cells perform in fighting real-world tumors. The dream is to create bespoke immunotherapies that can “train” a patient’s immune system to recall and relentlessly attack their specific type of cancer.
This breakthrough also has implications beyond ovarian cancer. If aNK cells can form memories of tumor types, it’s possible they could be used to target a wider range of hard-to-treat malignancies—including pancreatic, lung, and brain cancers—where existing immune treatments often fail.
As science continues to unravel the complexities of the immune system, findings like these challenge long-standing dogmas and open up exciting therapeutic frontiers. Natural killer cells were once thought to be fast but forgetful. Now, thanks to the pioneering work of researchers at Karolinska Institutet, we know that some of them never forget—and they’re ready to fight.
Source: Karolinska Institutet
