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What is Mesothelioma?

Most cancers are named for the organ or tissue they come from. That is true of mesothelioma as well. Whereas breast cancer begins at the breast and prostate cancer begins at the prostate, mesothelioma begins at the mesothelium.

The mesothelium is a thin, slick membrane that covers the lungs, heart, organs of the abdomen, and other vital bits of internal anatomy.

This membrane consists of two separate layers with a small amount of space between them. One layer is called the visceral and it faces the organs. The other layer is called the parietal and it faces the inside wall of the body cavity. Each layer is made up of a massive number of flat cells.

The mesothelium is not particularly impressive looking—certainly not as impressive in appearance as any of the organs it covers. Even so, the work it does is quite impressive.

Its main job is to act as a cushiony buffer between the organs and the body cavity. Without that buffer, the organs would rub against the cavity and produce much pain. However, the mesothelium plays other essential roles.

For one, it helps fight off diseases—including cancer—and bacterial or viral infections. For another, the mesothelium helps carry needed fluids to help nourish the organs . It also aids in repairing damaged cells and tissues, as well as promoting wound healing.

Every organ, every tissue, every part of the body is made up of cells.

Cells are machine-like organisms that begin life after an already existing cell divides. They grow, reproduce, age, and then eventually die. They are like machines in that they are programmed to perform very specific tasks that contribute to the smooth functioning of the entire body.

It sometimes happens, however, that this intricate microbiological machinery goes haywire. In the event that the cells’ programming malfunctions or their internal mechanisms breakdown, the cells are then classified as “damaged.”

Damaged cells are supposed to self-destruct. But they don’t always. Instead, they continue to grow, uncontrolled and swiftly, causing harm to the body.

That’s what cancer is—damaged cells running amok.

One of the ways normal, healthy cells become cancerous is through a change in their DNA. This can happen as a result of genes passed down from generation to generation.

Or it can happen after the DNA is damaged by exposure to environmental contaminants. In the case of mesothelioma, the only known environmental contaminant capable of damaging the DNA of mesothelium cells is the mineral asbestos.

According to the National Cancer Institute of the National Institutes of Health, the genetic changes that contribute to cancer tend to affect three main types of genes—proto-oncogenes, tumor-suppressor genes, and DNA repair genes. These changes are sometimes called “drivers” of cancer.

Proto-oncogenes are involved in normal cell growth and division. As the National Cancer Institute explains: “[W]hen these genes are altered in certain ways or are more active than normal, they may become cancer-causing genes (or oncogenes), allowing cells to grow and survive when they should not.”

Tumor-suppressor genes are also involved in controlling cell growth and division. Cells with certain alterations in tumor-suppressor genes may divide in an uncontrolled manner, says the National Cancer Institute.

DNA repair genes are involved in fixing damaged DNA. “Cells with mutations in these genes tend to develop additional mutations in other genes and changes in their chromosomes, such as duplications and deletions of chromosome parts. Together, these mutations may cause the cells to become cancerous,” the National Cancer Institute reports.

Mesothelioma cells behave nothing at all like normal mesothelium cells. For example, mesothelioma cells pay no attention to biological signals that tell them to stop growing, stop dividing, and start self-destructing.

Another abnormal behavior fostered by mesothelioma is cell mobility. Normal cells don’t move around and crowd out neighboring cells. They don’t spread throughout the body. Mesothelioma cells do.

Also, mesothelioma cells—after they clump together to form a tumor—attract blood vessels (an impossibility for normal cells) in order to nourish and fuel the growing mass.

Something else normal mesothelium cells can’t do (but mesothelioma cells can) is block the immune system from attacking and destroying them after they become damaged and fail to self-destruct. They also can’t force the immune system to become their defender. Yet mesothelioma cells are capable of these very feats.

In every three cases out of four, mesothelioma begins on the mesothelium surrounding the lungs. This mesothelial structure is called the pleura—and because the cancer starts there it is known as pleural mesothelioma.

Seen less often is peritoneal mesothelioma, which begins on the lining of the abdominal cavity (the peritoneum). Rarer is pericardial mesothelioma (it starts on the pericardium, the sac that surrounds the heart). Rarest of all is testicular mesothelioma, which begins on the tunica vaginalis of the testis.

Mesothelioma tumors don’t usually mushroom in all directions as do those associated with other forms of cancer. Rather, they tend to grow flat in a sheet-like pattern that eventually spreads across the pleura, the peritoneum, the pericardium, or the tunica vaginalis.

As the sheet of cancer cells expands, it causes the functioning of the mesothelium to decrease and eventually cease functioning.

Long before that, many mesothelioma cells break away from the mesothelium and travel throughout the body. They are carried along by the bloodstream or via the lymph system. Wherever the mesothelioma cells land, they begin growing and spreading there too.

You can read more about mesothelioma and learn how to fight it by visiting this page. There you’ll find a detailed guide, yours free for the asking.