[Reading Science] Why Can't We See Cancer Even When It's Right in Front of Us?

Cancer's Camouflage Strategies That Deceive the Immune System

Cancer develops within our bodies. Although it constantly encounters immune cells, in many cases, cancer continues to proliferate as if nothing is wrong. The question scientists have long asked is simple: "Why doesn't the immune system recognize the cancer right in front of it?"

Recently, international research teams have begun to unravel answers to this question at the molecular level. The true nature of the "immune evasion strategies" that allow cancer cells to survive by escaping immune surveillance is now being revealed in concrete detail.

Photo to aid understanding of the article. Medical staff performing laparoscopic surgery for pancreatic cancer. The Asia Business Daily DB.

How Does Pancreatic Cancer Hide from the Immune System?

Pancreatic cancer, considered one of the most intractable cancers, is known for its poor response to immunotherapy. Recently, an international research team led by the University of Wuerzburg in Germany discovered that pancreatic cancer cells deceive the immune system by using a molecular mechanism that blocks immune alarm signals at their source.

This study was led by Leonie Uhl, Amel Aziba, and Sinah Lobbert, among others, and the results were published in the international journal Cell. The researchers confirmed that pancreatic cancer cells neutralize the initial signals that allow immune cells to recognize cancer, using a specific molecular pathway.

In animal experiments, when this pathway was blocked, immune cells were once again able to recognize the cancer cells, and rapid tumor collapse was observed. The researchers explained, "Rather than attacking the cancer directly, enabling the immune system to 'see' the cancer may be the key to treatment."

'Sugar Coating': How Cancer Hides... and How Antibodies Unmasked It

A research team at Northwestern University in the United States also recently reported that pancreatic cancer cells evade immune attacks by using sugar-based camouflage signals, known as "sugar coating."

Mohamed Abdel-Mohsen, the lead researcher, explained, "The sugar structures on the surface of cancer cells send false signals to immune cells, blocking their attack." The team developed an experimental antibody that removes this camouflage signal, and in animal models, they observed that T cells and natural killer (NK) cells were reactivated to attack the cancer.

Photo to aid understanding of the article. Provided by Pixabay

Professor Abdel-Mohsen stated, "This study provides an important clue as to why pancreatic cancer has resisted immunotherapy. Antibody-based approaches could become a new treatment strategy, different from existing immune checkpoint inhibitors."

Immune evasion by cancer is not limited to the cell surface. Researchers at the Ludwig Institute for Cancer Research found that vitamin A metabolites play a role in weakening immune cell function and thereby promoting cancer growth.

According to their research, certain breakdown products of vitamin A suppress activation signals in immune cells and reduce the effectiveness of cancer vaccines and immunotherapies. Conversely, when this metabolic pathway was blocked, immune responses were restored and tumor growth slowed. These findings demonstrate that immune evasion by cancer is closely linked to the metabolic environment.

Cancer's Strategies Are Not Singular

Recent researchers describe cancer's immune evasion strategies in three major categories: camouflage, coercion, and cytoprotection.

Cancer cells disguise themselves as normal cells to avoid immune detection, directly suppress immune cell function, and simultaneously activate protective mechanisms that allow them to survive in low-oxygen and nutrient-deficient environments. This is why it is difficult to defeat cancer with a single treatment approach.

As a result, there is a growing call for multi-layered treatment strategies that combine immune checkpoint inhibitors, antibody therapies, cancer vaccines, cell therapies (CAR-T, CAR-NK), and metabolic regulation approaches.

The message from recent studies is clear: directly attacking cancer alone is not enough. Enabling the immune system to recognize cancer-that is, dismantling the camouflage strategies cancer has constructed to hide itself-is emerging as the key front in treatment.

Although most of this research is still at the animal experiment and early study stages, scientists believe that this approach could change the landscape of treatment for intractable cancers, including pancreatic cancer. Cancer has been right before our eyes, yet unseen. Now, science is beginning to unveil its cloak.