Can Dendritic Cell Vaccination Stop Mesothelioma?

One of the ways to treat mesothelioma is using science to help the patient’s own immune system fight the cancer.

The FDA has already approved immunotherapy for mesothelioma that blocks certain proteins to make the patient’s immune system T cells more attack-oriented against cancer cells.

Another method of immunotherapy is giving patients specific immune system cells that already know how to find mesothelioma cells. Doctors in Belgium tried this approach – called dendritic cell vaccination – on 10 people diagnosed with malignant mesothelioma, and the results are highly encouraging.

 

What Are Dendritic Cells?

Dendritic cells are a type of immune cell that help the immune system recognize foreign antigens – such as cancer cells – and present those antigens to other immune cells to trigger a response.

Think of dendritic cells as the alarm system. When cancer forms and begins spreading in your body, dendritic cells can find them and realize they should not be here. The dendritic cells then attach to the cancer cells and download whatever properties help distinguish these cancer cells from healthy cells – such as proteins that are unique to the cancer or overexpressed by the cells.

Dendritic cells then bring this information to the body’s T cells, which are the security guards. Once the alarm sounds in the body, the security guards begin patrolling and looking for cancer cells with the information given to them by the dendritic cells.

Dendritic cells are found throughout the body, including near the lungs and abdomen. Pleural mesothelioma forms in the lining of the lungs. Peritoneal mesothelioma forms in the lining of the abdominal cavity. These are the two main types of mesothelioma.

 

Why Can’t Dendritic Cells Stop Mesothelioma Without Treatment Help?

Mesothelioma is a fast-spreading cancer, and sometimes the immune system cannot keep up with the speed at which cells multiply and tumors grow. Our body’s immune system also struggles to fight cancer because the diseased cells look so similar to healthy cells.

How Cancer Forms

Cancer is not a foreign invader like a virus. It comes from our own healthy cells undergoing genetic mutations. Our body’s cellular makeup is a delicate balance consisting of a repeating cycle where cells multiply and die to maintain proper biological function.

When cells suffer genetic mutations, they can stop dying when they’re supposed to. They also replicate and form new cells faster, and these new cells have the same genetic mutations, which repeats the cycle of multiplying quickly and dying slowly.

This causes a cellular imbalance, which creates tumors that can overrun vital organs and disrupt necessary body functions.

Cancer Cells Look Like Healthy Cells

Even after the cells mutate into cancer, they still contain many of the same properties as they did when they were considered “healthy cells.” This means they still look in many ways like healthy cells.

The immune system often struggles to recognize cancer cells as dangerous. Dendritic cells may encounter mesothelioma cells but not notice enough of a difference to sound the alarm.

 

What Is Dendritic Cell Vaccination?

Dendritic cell vaccination is a type of cancer immunotherapy in which dendritic cells are altered to make them more effective at stimulating an anti-cancer response from the immune system.

Scientists can remove a patient’s dendritic cells and have them modified in a laboratory to carry specific antigens (proteins) carried by the tumor. This essentially downloads into the dendritic cells those characteristics that are unique to the cancer cells.

The modified dendritic cells are returned to the patient, where they find T cells and signal the alarm. The T cells then swarm to the site of the tumor and begin looking for and attacking cancer cells with those very specific antigen properties.

 

What the Study in Belgium Discovered

Scientists in Belgium studied the effectiveness of a dendritic cell vaccination that targeted the Wilms’ tumor protein (WT1). This protein is present in several types of cancer, including mesothelioma.

Scientists injected WT1-carrying dendritic cells into 39 patients, and 10 of them had malignant pleural mesothelioma. The median overall survival for those 10 patients was an astounding 48.8 months (4 years).

For comparison, the average mesothelioma survival for people who do not have surgery is 1-2 years. When the cancer is advanced – as it was for the 10 patients in this study – the expected survival is closer to 1 year than 2 years. So an average survival of 4 years far exceeds the baseline of success.

Scientists also examined the biological effects of the dendritic cell vaccination. They found increased responses from T cells in patients who did the best, suggesting that the dendritic cells are crucial in the fight against cancer.