New Mesothelioma Treatment - A 2010 Space Odyssey

When you read a medical science article, you might see technical terminology that can baffle the brightest minds. But when you understand what those terms mean, you can see that your inner space is just as exciting and strange as science fiction's outer space. The story of how the body's immune system works is like reading a science fiction novel full of strange creatures, weapons and a plot to overthrow civilizations. This is one such story that tells of a breakthrough in treating mesothelioma cancer and provides hope for those afflicted with the disease.

On February 18, 2010, an academic paper was published in the relatively obscure American Journal of Respiratory and Critical Care by a group of 9 scientists from the Netherlands. They reported a unique immunotherapy approach, called dendritic cell vaccination, for treating mesothelioma cancer. Mesothelioma cancer is a form of cancer that has been linked to asbestos exposure and can affect the lungs, abdomen and the heart. Immunotherapy is a therapy that beneficially manipulates the body's immune system to fight disease. To understand the importance of this discovery and what a dendritic cell approach is, we must first understand how both a cancer occurs and how the immune system works.

Think of your body as a futuristic city, and your skin as a force field that protects the city. Then imagine that one day, an alien life force slips past the outer defenses and into the city and begins to inhabit the bodies of the citizens living in this city. This is how cancer works. The DNA inside a healthy cell is mutated as if an alien life force has inhabited the cells. Scientists only have a theory as to why mutations occur (somatic mutation theory) but it is not proven.

Once these normal cells have mutated, they become zombie like cancer cells and begin to replicate their DNA to create new cancerous cells. These zombies walk amongst the living throughout the city. But there is one very peculiar aspect to them. These cancer cells are not recognized by the body's immune system as foreign invaders. The reason is that they have developed multiple anti-detection weapons that prevent the immune system from recognizing them.

To comprehend the nature of the cancerous anti-detection weapons, we have to first examine the weapons that the immune system possesses. Imagine that the immune system is an internal security force that patrols the body. The security force consists of different battle units.

At the front line are the scouts, called dendritic cells. When confronted by invading organisms, the dendritic cells collect molecular information called an antigen. Think of an antigen molecule as an organism's scent and the dendritic cells as sniffer dogs. When the dendritic cell detects an invader it immediately retrieves the antigen and moves to the battle garrisons called the lymph nodes. This is where all the battle units reside.

Once at the lymph node the dendritic cell communicates its scouting report to the commander called a T helper cell. The T helper cell puts the base on battle alert and passes the antigen information on to the destroyer cells. Each destroyer cell now has a copy of the invader's antigen to allow it to recognize and destroy the cancerous cells.

There are three main destroyer cells (white blood cells). There are the killer T cells (or cytotoxic T cell) which act as the infantry in the battalion. Once the killer T cells identify an invader (using the antigen they were given) they launch a chemical weapon (cytotoxin) that penetrates the invader and literally forces them to self destruct (apoptosis). Macrophages are the tanks in the army. They engulf and digest every invader in their path (phagocytosis). Then there are the combat engineers called B cells. When B cells are given their target antigen, they produce and launch millions of antigen seeking missiles called antibodies. The antibody is programmed to seek out any organism with the specific target antigen and attach itself to it. Once it is attached it destroys the organism by infection.

This seems like an impressive array of weapons that our bodies possess to destroy invaders but cancer cells have counter measure weapons to evade detection. One of these weapons is like a cloak of invisibility. Some cancer cells have the ability to alter their own DNA and in turn give themselves the ability to morph their outer appearance to resemble a healthy cell. It accomplishes this by submerging its own antigens from the surface of its cellular membrane when a dendritic cell is nearby and then resurfacing the antigen when the dendritic cell is gone (antigenic modulation).

And here is where the exciting development in cancer fighting begins. The Dutch scientists reached into this miniature battle ground and removed some of the cancer cells from the mesothelioma patients. They then extracted the antigens. It was a sort of kidnap and interrogate mission to find the cancer cell's secret antigen. A massive scouting group of 50 million dendritic cells were then given that specific antigen and were injected back into the patient's body. The scientists now hoped that the dendritic cells, armed with the correct scouting information on the invaders, would quickly travel to the lymph nodes to alert the battalion troops. If the destroyer cells could receive that specific antigen they could launch their forces and identify and destroy their targets.

The test results were very encouraging. They found an increase in antibodies and T cells, which meant that the dendritic cells had done their job in sounding the battle alert. The troops were on the move. Most importantly, they also found an increased level of cytotoxins (those chemical weapons used by the killer T cells) in the vicinity of the tumor. This was evidence that the fight had begun. Three out of ten patients in the study group showed signs of tumor regression.

When I think about the logic in this approach, it sounds so much more promising and ingenious than bombarding the entire body with chemotherapy and radiation which also kills healthy cells and produces long term side effects. It's like dropping a bomb in your own city to try to kill the invaders. I think that cancer researchers are providing much hope for a cancer cure with this unique form of immunotherapy.